Filbert Gateau with Praline Buttercream

This months' Daring Bakers challenge was to make a Filbert Gateau with Praline Buttercream. If you don't know what that is, don't worry...neither did I. I decided to play with this recipe and make some mini-cakes instead of one large one. I also decided to flavor it a bit with bananas, figuring it'd pair well with the hazelnut and chocolate in the original recipe.

Recipe:
Filbert Genoise:
1 1/2 c. hazelnuts, toasted and skinned
2/3 c. cake flour
2 T. cornstarch
7 large egg yolks
1 c. sugar (1/4 c. and 3/4 c. divided)
1 t. vanilla extract
1/2 t. lemon zest
5 large egg whites
1/4 c. warm, clarified butter

To toast and skin the hazelnuts, toss them onto a baking sheet and put into a 350ºF oven for about 12 minutes. Don't wait until you smell them cooking - by that point, they'll be burnt. Pull them out and set them in a tea towel, then wrap them up and let them steam for about 10 more minutes. Rub the towel together and most of the skins should come off. Pick the remaining skins off - if some won't come off, it's fine to leave a few.

Put the hazelnuts into a food processor and add cake flour and cornstarch. Process for 30 seconds, then pulse until a fine powder is obtained. Don't over-process, or you'll pull too much oil out of the nuts and make it a paste instead of a powder. Whisk the egg yolks until light in color, then add 3/4 c. sugar over the course of 3 minutes. This should get a ribbony texture. Add the lemon zest and vanilla, then mix to combine. In another bowl, whisk the egg whites into soft peaks. Slowly add the remaining 1/4 c. sugar, and whisk the eggs for 30 seconds. Add the egg yolks into the whites and fold until just combined. Add the hazelnut mixture into the egg mix, then add the clarified butter and fold until just combined. Pour into a mini-muffin pan, filling each mold about 2/3 of the way to the top. Bake for 10 minutes at 350ºF, or until the cakes are springy and coming away from the edges of the pan. Yields 48 mini cakes.


Simple syrup:
1 c. water
1/4 c. sugar
2 T. banana liqueur

Dissolve the sugar in water and simmer for 5 minutes. Remove from heat and add the liqueur, then allow to cool completely.

Swiss Buttercream:
4 large egg whites
3/4 c. sugar
3 sticks, butter
2 T. banana liqueur
1 T. vanilla extract

Whisk the egg whites together until they are nearly soft peaks. Move the egg whites into a double-broiler, and whisk in sugar 1 T. at a time, over the course of a minute. Continue to whisk the mixture until warm (about 120ºF) and becomes the consistency of thick marshmallows. With a paddle attachment on a stand mixer, beat these egg whites medium-high for 5-7 minutes or until a cool and thick meringue forms. Be careful not to over-beat the mix. Move this mixture to another bowl, and using the paddle attachment, beat the butter until it becomes smooth and creamy. Using medium-low speed, add the meringue to the butter over the course of 1 minute. Add the liqueur and vanilla, then mix until combined, thick, and creamy. Refrigerate this for at least 10-15 minutes before using so everything can set.


Praline paste:
1 c. hazelnuts, toasted and skinned
2/3 c. sugar

Line a jelly roll pan with butter and parchment paper. Place the sugar into a heavy 10-inch skillet and heat medium-low for 10-20 minutes or until it begins to melt around the edges. Don't stir the mix, but swirl it to mix in parts that aren't melting. When the sugar is fully melted and caramel in color, add the nuts and stir with a wooden spoon. Separate any clusters that form, and continue heating until it begins to bubble. Make sure all the hazelnuts have been coated. Pour onto the parchment paper and spread evenly to cool. Once at room temperature, carefully break the praline into pieces and place it into a food processor. Pulse into a powder, then continue processing until a thick paste is formed.

Praline Buttercream:
Full recipe of Swiss Buttercream
1/3 c. Praline Paste
2 T. banana liqueur

Blend 1/2 c. of the buttercream into the praline paste, then add this into the remaining buttercream. Whip on medium-low speed until combined. Pour in the liqueur and mix in. Refrigerate this mixture before using.


Nutella Whipped Cream:
3/4 c. heavy cream
2 T. Nutella

Whisk the heavy cream until it forms whipped cream, then add the Nutella and continue to whisk until combined thoroughly.

Banana Jam:
2 large bananas, overripe, frozen, and then thawed
1/2 c. sugar
1/4 c. water

Boil the water and sugar together, then add the bananas and boil, mashing with a fork. Continue to cook until reduced and thick.


Ganache Glaze:
6 oz. semi-sweet chocolate
3/4 c. cream
1 T. corn syrup
1 T. banana liqueur
3/4 t. vanilla extract

Chop the chocolate roughly and place into a bowl. Heat the cream and corn syrup in a pan over low heat until it forms a gentle boil. Pour the cream mixture over top of the chocolate, and let stand 1 minute before stirring with a fork. Blend in the vanilla and banana liqueur. If it appears oily, add a little hot water and it will begin to thicken.


Assembly:
Cut each of the mini-cakes in half, and brush with the simple syrup until all the syrup is used. On one half, spoon on some of the buttercream mixture, and add the nutella whipped cream on the other half. Place the halves together to form a cake and top with a bit of the banana jam. Top with the ganache glaze, and serve.

The cakes are extremely messy to eat, mainly because my buttercream didn't come together quite right. I don't blame the recipe, but rather my attempt at multi-tasking a bit too much. The mini-cakes are perfect for a large bite-sized treat, so it didn't matter too much that buttercream spreads all over the place. The banana, hazelnut, and chocolate flavors all play well together, making this dessert very tasty.