Melt dark chocolate gently, then mix in Nutella and fold in feuilletine. Spread on lined baking sheet and cut into a round to fit the bottom of the cake pan. Refrigerate until set.

Preheat oven to 350?F. Melt chocolate, cocoa powder, espresso powder, and butter with boiling water, then let cool.

In another bowl, mix flour, sugar, baking soda, and salt.

Whisk egg, yolk, sour cream, and oil into chocolate mixture. Combine wet and dry ingredients, then pour into prepared baking pan and bake for 28-30 minutes. Let cool completely.

Prepare a cake ring or springform pan with acetate. Place chilled croustillant base in bottom.

Cut chocolate cake into a round and place on the base. Spread raspberry jam on top and freeze until mousse is ready.

Soften gelatin in cool water.

Combine raspberry puree with lemon juice and warm gently. Add gelatin and whisk until dissolved.

Mix with melted ruby chocolate. Whip cream to soft peaks and fold into the chocolate mixture.

Pour or pipe mousse over cake and freeze until firm.

Soften gelatin in cool water.

Boil sugar, corn syrup, and water until sugar dissolves.

Add gelatin and mix until dissolved. Stir in sweetened condensed milk and cocoa.

Pour over chopped chocolate and mix until smooth. Let glaze cool to 95-98?F.

Remove cake from freezer, place on wire rack, and pour glaze over until covered. Allow excess to drip off.

Transfer to cake stand and refrigerate until ready to serve.