Cake: Preheat the oven to 200 degrees C. Line a baking tray or springform tin with baking paper and butter.
Separate eggs. Beat the egg yolks and vanilla with 2/3 of the sugar with an electric mixer until creamy.
In another bowl, beat egg whites with the remaining sugar until stiff. Add to the yolk mixture.
Mix flour, cornflour and baking powder then sift into the egg mixture. Fold everything thoroughly but carefully together with a spatula.
Pour the mixture into the tin and smooth out. Bake in the preheated oven for 25 minutes.
Remove the sponge from the cake tin. Carefully remove the baking paper. Cool on wire rack, then carefully slice into three layers.
Chocolate Mousse: Heat the cream with the chocolate and coffee until everything has dissolved. Mix well and leave to cool. Place in the refrigerator overnight.
Raspberry Filling: Bring the raspberries and sugar to the boil. Mix the cornflour with water and add to the raspberries. Bring to the boil while stirring constantly for 5 minutes or until the mixture is clear again. Allow to cool.
To Assemble: Spread the raspberry filling over the bottom layer of the cake then top with another layer of cake.
Beat the chocolate mousse with the cream stabiliser until stiff then spread about a third of it over the second layer of cake.
Top with the remaining cake layer then use the rest of the chocolate mousse to cover the top and sides of the cake. Refrigerate the cake until serving.