Buche de Noel

Source: Adapted from Nick Malgieri via the Food Network
Serves: 12

Chocolate Genoise
3 large eggs
3 large egg yolks
Pinch salt
3/4 cup sugar
1/3 cup cake flour (spoon flour into dry-measure cup and level off)
1/3 cup cornstarch
1/4 cup alkalized (Dutch process) cocoa

Mocha Buttercream
4 large egg whites
1 cup sugar
24 tablespoons (3 sticks) unsalted butter, softened
2 tablespoons strong brewed coffee
2 tablespoons rum or brandy
1/2 c chocolate chips, melted & slightly cooled

Marzipan
8 ounces almond paste
2 cups confectioners' sugar
3 to 5 tablespoons light corn syrup
Cocoa powder
Liquid food coloring

1. Make the Genoise
Butter and line a 15X10 inch sheet pan with parchment paper. Butter the parchment paper. Set rack in the middle of the oven and preheat to 400 degrees. Half-fill a medium saucepan with water and bring it to a boil over high heat. Lower the heat so the water is simmering.
Whisk the eggs, yolks, salt, and sugar together in the bowl of a heavy-duty mixer. Place over the pan of simmering water and whisk gently until the mixture is just lukewarm, about 100 degrees (test with your finger). Attach the bowl to the mixer and with the whisk attachment, whip on medium-high speed until the egg mixture is cooled (touch the outside of the bowl to tell) and tripled in volume.
While the eggs are whipping, stir together the flour, cornstarch, and cocoa.
Sift 1/3 of the flour mixture over the beaten eggs. Use a rubber spatula to fold in the flour mixture, making sure to scrape all the way to the bottom of the bowl on every pass through the batter to prevent the flour mixture from accumulating there and making lumps. Repeat with another 1/3 of the flour mixture and finally with the remainder.
Scrape the batter into the prepared pan and smooth the top. Bake the genoise for about 10 to 12 minutes, or until well risen, deep and firm to the touch. (Make sure the cake doesn't overbake and become too dry, or it will be hard to roll.)
Use a small paring knife to loosen the cake from the sides of the pan. Invert the cake onto a clean towel. Remove the paper and roll up the cake starting with the long side. Cool cake completely on a rack.

2. Make the Buttercream
Whisk the egg whites and sugar together in the bowl of an electric mixer. Set the bowl over simmering water and whisk gently until the sugar is dissolved and the egg whites are hot. Attach the bowl to the mixer and whip with the whisk on medium speed until cooled. Switch to the paddle and beat in the softened butter and continue beating until the buttercream is smooth. Beat coffee, rum, and chocolate into the buttercream. Set aside.

3. Make the Marzipan
Combine the almond paste and 1 cup of the sugar in the bowl of the electric mixer and beat with the paddle attachment on low speed until the sugar is almost absorbed. Add the remaining 1 cup sugar and mix until the mixture resembles fine crumbs. Add half the corn syrup, then continue mixing until a bit of the marzipan holds together when squeezed, adding additional corn syrup a little at a time, as necessary; the marzipan in the bowl will still appear crumbly. Transfer the marzipan to a work surface and knead until smooth.
Play with your food and shape as you wish. Mushrooms are traditional but we also made pears, cherries, acorns, and pinecones. Knead in cocoa or food coloring to make different colors. Dust on cocoa to make "dirt" or paint on dilute food color.

4. Assemble the Buche
Unroll the cooled cake and spread with half the buttercream. Roll the cake into a tight cylinder Transfer to baking sheet and refrigerate for at least 30 minutes or until set.
Trim the ends on the diagonal, starting the cuts about 2 inches away from each end. Position the cut pieces on the buche to resemble branches. Cover the buche with the reserved buttercream, making sure to curve around the protruding stump. Streak the buttercream with a fork or decorating comb to resemble bark. Transfer the buche to a platter and decorate with the marzipan.

Keep at cool room temperature. Cover leftovers loosely and keep at room temperature.