Chocolate Crunchy Cake

To glaze the nuts: Preheat the oven to 275 F. Spread the hazelnuts in a single layer on a baking sheet. Bake 12 to 15 minutes, until the nuts just begin darken. Remove and let cool just enough to handle, then rub the hot nuts with a towel to remove the bitter skins. Let cool completely.

Lightly grease a baking sheet. Combine the sugar, corn syrup, and water in a heavy saucepan over low heat and stir until the sugar is completely dissolved. Increase the heat to medium and cook without stirring until golden-brown in color, 300 F on a candy thermometer (hard-crack stage). Remove from heat and stir in the nuts. Immediately lift out the nuts with a wire lifter or slotted spoon and drain slightly over the pan, then spread on the greased baking sheet. Let cool. Set aside 45 of the best hazelnuts for garnish.

To make the praline feuillantines: In the top of a double boiler over barely simmering water, melt the chocolates together. Stir in the nuts and crushed crepes and blend. Spread out thin on a piece of parchment paper. Refrigerate until firm.

To make the praline mousse: Bring the cream just to the boiling point over medium-high heat. Put the chocolate and hazelnut (praline) paste in a heatproof bowl and pour the hot cream over them. Blend well and let cool. Fold in the whipped cream.

Place fifteen 2-1/2-inch ring molds on parchment-lined baking sheets. Cut the feuillantine into 2-1/2-inch circles and press one into the bottom of each mold. Fill each mold with praline mousse. Freeze until firm, at least 2 hours. Turn out of the molds, place on wire racks over the parchment-lined baking sheets, and return to the freezer.

To make the coffee crème anglaise: Add the coffee grounds to the milk in a heavy saucepan and bring to a boil. Take off the heat and let stand for 10 minutes. Beat the egg yolks and sugar until light in color and thickened. Whisk the coffee-milk mixture into the egg mixture and put back in the saucepan. Cook over medium heat until the mixture coats the back of a spoon, about 10 minutes. Remove and strain through a fine-meshed sieve. Cover with plastic wrap and refrigerate.

To make the paradise icing: Bring the water, sugar, cocoa powder, and cream to a boil in a heavy saucepan. Put the chopped chocolate in a heatproof bowl and pour the cream mixture over it. Blend well and stir until glossy. Let cool until lukewarm.

To assemble: Take the frozen molds out of the freezer and leave on the wire rack over the baking sheet. Pour the icing over the cakes to form a smooth coating. When the icing has congealed, lift a mold with a wide spatula and place on a dessert plate. With a knife which has been dipped in hot water, cut the cake in half and spread the sides apart. Repeat with remaining cakes. Spoon the coffee crème anglaise on the plate in the center opening of each cake. Garnish each with three glazed hazelnuts and a mint leaf.