Filbert Gateau with Praline Buttercream

July 2008 Daring Baker’s Challenge – Recipe by Carol Walter from her book ‘Great Cakes’

Cake Components:

•  1 Filbert Genoise (recipe follows)
• 1 recipe sugar syrup, flavored with dark rum (recipe follows)
• 1 recipe Praline Buttercream (recipe follows)
• ½ cup heavy cream, whipped to soft peaks
• 1 recipe Apricot Glaze (recipe follows)
• 1 recipe Ganache Glaze, prepared just before using (recipe follows)
• 3 tablespoons filberts, toasted and coarsely chopped

The following components can be prepared in advance: Clarified Butter, Apricot Glaze, Sugar Syrup, Praline Paste, Swiss Buttercream, Toasted Hazelnuts.  Store butter, glaze, syrup, and buttercream in air-tight containers in the refrigerator for up to 3 days.  Store paste and hazelnuts in air-tight containers at room temperature for up to 1 week.

Filbert Genoise

Because of the amount of nuts in the recipe, this preparation is different from a classic genoise.

Before preparing the cake, prepare the Apricot Glaze (see below) as you will be brushing this on the cake while it is still warm.

•  1 ½ cups hazelnuts, toasted/skinned
• 2/3 cup cake flour, un-sifted
• 2 Tbsp. cornstarch
• 7 large egg yolks
• 1 cup sugar, divided ¼ & ¾ cups
• 1 tsp. vanilla extract
• ½ tsp. grated lemon rind
• 5 lg. egg whites
• ¼ cup warm, clarified butter (100 – 110 degrees)

1. Position rack in the lower 3^rd of the oven and preheat to 350 degrees.  Grease and flour a 10″ X 2″ inch round cake pan (I have used a 9″ x 2″ cake pan with good results).  If you have parchment paper, cut a round of paper and place it in the bottom of the pan, greasing the top of the parchment as well.
2. Using a food processor, process nuts, cake flour, and cornstarch for about 30 seconds.  Then, pulse the mixture about 10 times to get a fine, powdery mixture.  You’ll know the nuts are ready when they begin to gather together around the sides of the bowl. While you want to make sure there aren’t any large pieces, don’t over-process.  Set aside.
3. Put the yolks in the bowl of an electric mixer, with the whisk attachment, and beat until thick and light in color, about 3-4 minutes on med-high speed. Slowly, add ¾ cup of sugar.  It is best to do so by adding a tablespoon at a time, taking about 3 minutes for this step.  When finished, the mixture should be ribbony.  Blend in the vanilla and grated lemon rind.  Remove and set aside.
4. Place egg whites in a large, clean bowl of the electric mixer with the whisk attachment and beat on medium speed, until soft peaks. Increase to med-high speed and slowly add the remaining ¼ cup of sugar, over 15-20 seconds or so.  Continue to beat for another ½ minute. 
5. Add the yolk mixture to the whites and whisk for 1 minute.
6. Pour the warm butter in a liquid measure cup (or a spouted container). * It must be a deep bottom bowl and you must work fast.* Put the nut meal in a mesh strainer (or use your hand – working quickly) and sprinkle it in about 2 tablespoons at a time – folding it carefully for about 40 folds.   Be sure to exclude any large chunks/pieces of nuts. Again, work quickly and carefully as to not deflate the mixture. When all but about 2 Tbsp. of nut meal remain, quickly and steadily pour the warm butter over the batter.  Then, with the remaining nut meal, fold the batter to incorporate, about 13 or so folds.
7. With a rubber spatula, transfer the batter into the prepared pan, smoothing the surface with the spatula or back of a spoon. **If collected butter remains at the bottom of the bowl, do not add it to the batter!  It will impede the cake rising while baking.
8. Tap the pan on the counter to remove air bubbles and bake in the preheated oven for 30-35 minutes. You’ll know the cake is done when it is springy to the touch and it separates itself from the side of the pan.  Remove cake from oven and allow to stand for 5 minutes.  Invert onto a cake rack sprayed with nonstick coating, removing the pan. 
9. Brush the cake top and sides with Apricot Glaze.  If the glaze has cooled, warm briefly in the microwave.
10. Cool the cake completely.
11. If not using the cake right away, wrap thoroughly in plastic wrap, then in a plastic bag, then in the refrigerator for up to 3 days. If freezing, wrap in foil, then the bag and use within 2-3 months.

 Sugar Syrup

 Makes 1 cup, good for one 10-inch cake – split into 3 layers

• 1 cup water
• ¼ cup sugar
• 2 Tbsp. dark rum or orange flavored liqueur

1. In a small, yet heavy saucepan, bring the water and sugar to a boil and simmer for 5 minutes. Remove from heat, add the liqueur. Cool slightly before using on the cake.  *Can be made in advance.

Apricot Glaze

Good for one 10-inch cake

• 2/3 cup thick apricot preserves
• 1 Tbsp. water

1. In a small, yet heavy saucepan, bring the water and preserves to a slow boil and simmer for 2-3 minutes. If the mixture begins to stick to the bottom of the saucepan, add water as needed.
2. Remove from heat and, using a strainer, press the mixture through the mesh and discard any remnants. With a pastry brush, apply the glaze onto the cake while the cake is still warm.  If the glaze is too thick, thin to a preferred consistency with drops of water.

Praline Buttercream

• 1 recipe Swiss Buttercream (see below)
• 1/3 cup praline paste (see below)
• 1 ½ – 2 Tbsp. Jamaican rum (optional)

1. Blend ½ cup buttercream into the paste, then add to the remaining buttercream.  Whip briefly on med-low speed to combine.  Blend in rum.

Swiss Buttercream

• 4 lg. egg whites
• ¾ cup sugar
• 1 ½ cups (3 sticks) unsalted butter, slightly firm
• 1 ½ -2 Tbsp. Grand Marnier or liqueur of your choice
• 1 tsp. vanilla

1. Place the egg whites in a lg/ bowl of a electric mixer and beat with the whisk attachment until the whites are foamy and they begin to thicken (just before the soft peak stage). Set the bowl over a saucepan filled with about 2 inches of simmering water, making sure the bowl is not touching the water. Then, whisk in the sugar by adding 1-2 tablespoon of sugar at a time over a minutes time. Continue beating 2-3 minutes or until the whites are warm (about 120 degrees) and the sugar is dissolved.  The mixture should look thick and like whipped marshmallows.
2. Remove from pan and with either the paddle or whisk attachment, beat the egg whites and sugar on med-high until its a thick, cool meringue – about 5-7 minutes. *Do not overbeat*. Set aside.
3. Place the butter in a separate clean mixing bowl and, using the paddle attachment, cream the butter at medium speed for 40-60 seconds, or until smooth and creamy. *Do not overbeat or the butter will become toooooo soft.*
4. On med-low speed, blend the meringue into the butter, about 1-2 Tbsp. at a time, over 1 minute.  Add the liqueur and vanilla and mix for 30-45 seconds longer, until thick and creamy.
5. Refrigerate 10-15 minutes before using.

Wait! My  buttercream won’t come together! Reheat the buttercream briefly over simmering water for about 5 seconds, stirring with a wooden spoon. Be careful and do not overbeat. The mixture will look broken with some liquid at the bottom of the bowl. Return the bowl to the mixer and whip on medium speed just until the cream comes back together.

Wait! My buttercream is too soft! Chill the buttercream in the refrigerator for about 10 minutes and rewhip. If that doesn’t work, cream an additional 2-4 Tbsp. of butter in a small bowl- making sure the butter is not as soft as the original amount, so make sure is cool and smooth. On low speed, quickly add the creamed butter to the buttercream, 1 Tbsp. at a time.

Refrigerate in an airtight container for up to 5 days, or can be frozen for up to 6 months. If freezing, store in 2 16-oz. plastic containers and thaw in the refrigerator overnight or at room temperature for several hours.

Praline Paste

• 1 cup (4 ½ oz.) Hazelnuts, toasted/skinless
• 2/3 cup Sugar

1. Line a jelly roll pan with parchment and lightly butter.
2. Put the sugar in a heavy 10-inch skillet.  Heat on low flame for about 10-20 min until the sugar melts around the edges. Do not stir the sugar. Swirl the pan if necessary to prevent the melted sugar from burning.  If the sugar does not start to melt, turn the heat up a bit.  Brush the sides of the pan with water to remove sugar crystals.  If the sugar in the center does not melt, stir briefly.
3. When the sugar is completely melted and caramel in color, remove from heat. Stir in the nuts with a wooden spoon and separate the clusters. Return to low heat and stir to coat the nuts on all sides.  Cook until the mixture starts to bubble.  **Remember – extremely hot mixture.**
4. Pour the hot mixture onto the parchment lined sheet and spread as evenly as possible. As it cools, it will harden into brittle. Break the candied nuts into pieces and place them in the food processor.  Pulse into a medium-fine crunch or process until the brittle turns into a powder. To make paste, process for several minutes.
5. Store in an airtight container and store in a cook dry place.  Do not refrigerate.

Whipped Cream

Good for one 9 or 10-inch cake

• 1/2 cup heavy whipping cream

1. Place a metal or glass bowl along with the beater(s) from your mixer in the freezer for 15 minutes.
2. Add the cold cream to the bowl and beat at med-high speed until soft peaks form.  Do not over-beat. 
3. Store, covered, in the refrigerator for 1 day.

Ganache Glaze

Makes about 1 cup, enough to cover the top and sides of a 9 or 10 inch layer or tube cake

**Ganache can take on many forms.  While warm – great fudge sauce.  While cool or lukewarm – semisweet glaze. Slightly chilled – can be whipped into a filling/frosting. Cold & solid – the base of candied chocolate truffles.

• 6 oz. (good) semisweet or bittersweet chocolate, like Lindt
• 6 oz. (¾ cup heavy cream
• 1 tbsp. light corn syrup
• 1 Tbsp. Grand Marnier, Cointreau, or dark Jamaican rum (optional)
• ¾ tsp. vanilla
• ½ – 1 tsp. hot water, if needed

1. Blend vanilla and liqueur/rum together and set aside.
2. Break the chocolate into 1-inch pieces and place in the basket of a food processor and pulse until finely chopped.  Transfer into a medium sized bowl and set aside.
3. Heat the cream and corn syrup in a saucepan, on low, until it reached a gentle boil.  Once to the gently boil, immediately and carefully pour over the chocolate.  Leave it alone for one minute, then slowly stir and mix the chocolate and cream together until the chocolate is melted and incorporated into the cream. Carefully blend in vanilla mixture. If the surface seems oily, add ½ – 1 tsp hot water. The glaze will thicken, but should still be pourable. If it doesn’t thicken, refrigerate for about 5 minutes, but make sure it doesn’t get too cold!

Assembling the Cake  

1. Cut a cardboard disk slightly smaller than the cake.  Divide the cake into 3 layers and place the first layer top-side down on the disk. Using a pastry brush, moisten the layer with 3-4 Tbsp. of warm sugar syrup. Measure out 1 cup of praline buttercream and set aside.
2. Spread the bottom layer with a ¼-inch thickness of the remaining buttercream.  Cover with ½ of the whipped cream, leaving ¼-inch border around the edge of the cake.  Place the middle layer over the first, brush with sugar syrup, spreading with buttercream. Cover with the remaining whipped cream.
3. Moisten the cut side of the third layer with additional sugar syrup and place cut side down on the cake.  Gently, press the sides of the cake to align the layers. Refrigerate to chill for at least 30 minutes.
4. Lift the cake by sliding your palm under the cardboard. Holding a serrated or very sharp night with an 8-ich blade held parallel to the sides of the cake, trim the sides so that they are perfectly straight. Cut a slight bevel at the top to help the glaze drip over the edge.  Chill while you prepare the ganache.
5. Place a rack over a large shallow pan to catch the ganache drippings.  Remove the gateau from the refrigerator and put it the rack. With a metal spatula in hand, and holding the saucepan about 10 inches above the cake, pour the ganache onto the cake’s center.  Move the spatula over the top of the ganache about 4 times to get a smooth and mirror-like appearance.  The ganache should cover the top and run down the sides of the cake. When the ganache has been poured and is coating the cake, lift one side of the rack and bang it once on the counter to help spread the ganache evenly and break any air bubbles. (Work fast before setting starts.) Patch any bare spots on the sides with a smaller spatula, but do not touch the top after the “bang”.  Let the cake stand at least 15 minutes to set after glazing.
6. To garnish the cake, fit a 12 – 14-inch pastry bag with a #114 large leaf tip. Fill the bag with the reserved praline cream.  Starting ½ inch from the outer edge of the cake, position the pastry tube at a 90 degree angle with the top almost touching the top of the cake. Apply pressure to the pastry bag, moving it slightly toward the center of the cake.  As the buttercream flows on the cake, reverse the movement backward toward the edge of the cake and finish by pulling the bag again to the center. Stop applying pressure and press the bag downward, then quickly pull the tip up to break the flow of frosting.  Repeat, making 12 leaves evenly spaced around the surface of the cake.
7. Make a second row of leaves on the top of the first row, moving the pastry bag about ¾ inch closer to the center.  The leaves should overlap.  Make a 3^rd row, moving closer and closer to the center. Add a 4^th row if you have the room. But, leave a 2-inch space in the center for a chopped filbert garnish. Refrigerate uncovered for 3-4 hours to allow the cake to set. Remove the cake from the refrigerator at least 3 hours before serving.
8. Leftover cake can be covered with foil and kept in the refrigerator for up to 5 days.

Additional instructions:

To make clarified butter:

• 1 stick unsalted butter

1. Melt butter in a small saucepan over low heat.  Remove from the heat and set aside for 10 minutes.  At this point, the fat will rise to the surface.  Using a spoon, skim off as much of the fat as possible, while leaving the yellow, clarified butter behind.  Next, carefully pour off the clear yellow butter into a separate container, leaving as much of the milk fat in the bottom of the pan as possible.  You should now be left with approximately ¼ cup of clarified butter, just enough for the cake recipe.  You can refrigerate the butter until you are ready to use it.

To toast and skin filberts (hazelnuts):

1. Pre-heat oven to 400 deg F.
2. Spread hazelnuts on an ungreased baking sheet.  Bake for 10 minutes.
3. Place warm hazelnuts in a kitchen towel and wrap up for 5 minutes (this will steam the nuts, causing the skins to be more easily removed).  After 5 minutes, rub the hazelnuts together briskly inside the towel.  You should be able to remove most of the skins with this method.  Don’t worry if you don’t get all of the skins off, if some remain, it won’t the recipe.