In a bowl, mix the flour with a little salt. In another bowl, mix the cocoa with boiling water, then add sugar and oil. Stir in the eggs and vanilla, then the flour and salt. Bake the prepared mixture in a pan no. 28 at 170° C, about 20 minutes. Halve the cooled sponge cake. To prepare the mousse, melt the chocolate and butter on steam. Add the cocoa. When the mixture cools slightly, add the beaten egg yolks that you have previously steamed. Stir well. Whisk the whites and add the chocolate mixture. Whisk the sweet cream and add it to the mixture. Line the bottom of the pan where the sponge cake was baked with the first half of the sponge cake, and top it with 80% of the mixture with the chocolate mousse. Top it with a whole layer of fresh raspberries. Put the second sponge cake, then the rest of the mixture with the mousse. Leave in the refrigerator to harden. After two hours, in a steamer, melt the chocolate together with the butter and pour the mixture over the top of the cake. Leave the cake prepared in this way in the refrigerator until serving. Decorate as desired.