4 oz heavy cream 4 oz dark chocolate, coarsely chopped
4 oz milk chocolate, coarsely chopped
1Preheat oven to 375F. Lightly grease a 10×15-inch roll pan and line the bottom with parchment paper.
2In a medium bowl, sift together flour, cocoa powder, baking powder, baking soda and salt.
3In a large bowl, beat together egg yolks and 1/3 cup sugar until sugar is dissolved and mixture has doubled in volume. Stir in one third of the flour mixture, followed by half of the water and the vanilla extract. Stir in another third of the flour mixture, followed by the rest of the water and the remaining flour mix.
4In another large bowl, beat egg whites until they are very foamy. With the mixer on high, gradually blend in remaining 1/2 cup sugar, beating until the egg whites hold soft peaks. Fold egg whites into the chocolate mixture.
5Pour cake batter into prepared pan and spread into an even layer.
6Bake for 11-15 minutes, or until the cake springs back when lightly pressed. Run a knife around the edge of the pan and turn the cake out onto a cooling rack. Peel back parchment paper and allow cake to cool completely.
7Line a 9×5-inch loaf pan with plastic wrap.
8Cut pieces of the chocolate cake to fit the bottom, sides and the top of the pan. If you find that you need to mix and match sizes, the best pieces to fudge the shape are the edges.
9Place the bottom and size pieces into place. Fill the cake cavity half way up with ice cream and spread into an even layer. Place three rows of four Waffeletten cookies each into the ice cream, then fill the pan almost to the top with the remaining ice cream. Place the top piece of cake into place, wrap the pan firmly in plastic wrap and freeze until solid, at least 6 hours.
10When cake is frozen and you are ready to serve, prepare the ganache glaze.
11In a small saucepan, bring cream to a simmer.
12In a medium bowl, combine dark and milk chocolate. Pour simmering cream over the chocolate and stir gently with a spatula until the chocolate melts. If necessary, reheat mixture in 10-15 second intervals in the microwave if the chocolate does not melt completely. Allow ganache to cool and thicken slightly, about 10-15 minutes.
13Pour ganache over the cake, using an offset spatula to spread it into an even layer on the top and sides. Ganache will set in 1-3 minutes. Place cake onto cake plate and serve immediately, using a sharp knife to cut slices. Leftovers can be stored in the freezer.