Vanilla-Bourbon Génoise with Bourbon Buttercream

1. Preheat oven to 350°F with a rack in the center. Butter and flour a 10x2-inch round cake pan.

2. For the génoise, beat the eggs, one yolk, 1/3 cup sugar, and 1 1/2 tsp. vanilla in the bowl of an electric mixer or another large stainless-steel bowl, passing the bowl over a flame a few times, until it is about body temperature; or beat with a hand mixer in a bowl set over another bowl of hot water. (When you dip your finger in, you should not feel any change in temperature.) Then beat on medium speed for 8 to 10 minutes or until the mixture quadruples in volume. Sift the flour directly on top of mixture, folding it in gently until well combined. Add the melted butter by sprinkling it on top of the batter and gently folding it in. If poured in too quickly, the butter will sink to the bottom of the bowl and will tend to break down the batter, so be gentle and do not overfold.

3. Pour into the prepared cake pan, place on a cookie sheet, and bake 25 to 30 minutes, until the cake is nicely browned and the sides have shrunk slightly from edges of pan. Remove from the oven and keep in a warm place for 15 to 20 minutes before unmolding.

4. Meanwhile, for the bourbon syrup, mix the warm water, 1 tsp. vanilla, 2 Tbsp. sugar, and 3 Tbsp. bourbon together in a bowl until the sugar dissolves. Set aside. Unmold the cake onto a wire rack. When cool, place in a plastic bag and chill.

5. For the buttercream, combine 1 cup sugar and 1/4 cup water in a heavy medium saucepan. Bring to boiling; remove from heat. Place the six egg yolks in a bowl and lightly beat. Gradually whisk about half of the hot sugar mixture into yolks. Gradually whisk egg yolk mixture into remaining sugar mixture in saucepan. Bring to a gentle boil; reduce heat. Cook and stir 2 minutes. Remove from heat. Stir in 1 Tbsp. bourbon and 1 1/2 tsp. vanilla.

6. Transfer yolk mixture to a bowl. Fill a larger bowl with cold water and ice. Place smaller bowl into the larger bowl. Stir yolk mixture frequently about 10 minutes or until cooled to room temperature.

7. In the bowl of an electric mixer bowl beat the softened butter on high until fluffy. Add cooled yolk mixture, beating until combined. If necessary, chill until mixture reaches spreading consistency.

8. To build the cake, Jacques cuts the cake into three very thin layers, but this can be tricky to do evenly at home. Instead, we cut the cake into two layers. Whichever you choose, use a long, serrated knife. Jacques's tip for nice even layers is to keep the blade level and still, and rotate the cake (rather than pulling the knife through the stationary cake). He also suggests using guides such as spatula handles to keep the knife level as you cut. Place spatulas with 3/8- or 1/2-inch-thick handles on either side of cake; rest knife on guides as you cut.

9. Cut a piece of cardboard the size of the bottom of the cake. For three layers, place first layer, from the cake top, upside down on the cardboard. Brush with bourbon syrup. Spread a thin layer of buttercream on top. Add second layer. Brush with syrup and coat with buttercream. Place third layer on top, brush with remaining syrup, and coat top with buttercream, spreading it as smoothly as you can with a long, thin metal spatula. Spread buttercream as smoothly as possible around cake sides.

10. Melt the chocolate and add a few drops of oil to it. Make a cornet (a parchment paper cone for piping) and pour chocolate into it. Cut off the tip; draw a design to your liking on top of the cake. Fill a pastry bag fitted with desired tip with remaining buttercream. Pipe a pattern all around top edge of cake. Refrigerate until serving time. (If the cake is to be kept for several hours, cover with plastic wrap once buttercream sets to prevent it from absorbing the flavors of foods in the refrigerator.)

For the Cover Version:

For the six-layer version featured on BHG's 100th Anniversary cover, bake Jacques's cake recipe three times in 9-inch pans (same temperature and timing), then split each cake in half to create 6 layers total. Double the buttercream for frosting and piping.