Chocolate Ice Cream Cake
Cut the vanilla pod in half and scrape out the inside. Add to the milk and bring to a boil.
Beat the egg yolks until creamy with the sugar. Remove the vanilla bean from the milk and slowly stream the milk into the egg yolks. Transfer back into the pot and stir continuously over low heat until thick and creamy. Place the pot over ice water and continue to stir until cool, about 15 minutes. Add the cognac and allow to cool completely in the refrigerator.
Melt the chocolate in a bowl over a pot of hot water.
Whip the cream. Separate the cream in half and fold half of the cream into the chocolate.
Fold the other half into the custard.
Trim the ladyfinger to the size of the springform pan.
Place the sponge cake on the bottom of a springform pan. Line the inside of the pan with the trimmed ladyfingers. Spread first the custard into the pan and then spread the chocolate cream on top. Freeze for at least 3 hours.
Before serving, remove from the freezer and remove from the pan. Shave chocolate with a vegetable peeler to form chocolate curls. Sprinkle the curls over the cake and then dust with cocoa powder. Serve immediately.