Sachertorte with chocolate mousse layers

Beat the cubed almond paste with the sugar using the paddle, adding the egg yolk and egg mixture little by little until smooth and lump-free.

Scrape down the bowl, switch to the whisk and beat on high for 10 minutes; transfer to a large bowl.

Beat the egg whites to stiff peaks, adding sugar gradually, to make a meringue; have the oven on before starting.

Fold a third of the meringue into the almond mixture, then the sifted flour and cocoa powder, then the remaining meringue, then the melted butter.

Spread on a lightly oiled silicone mat and bake at 380F (190C) for about 12 minutes; the biscuit can be made a day ahead and refrigerated.

Top with parchment paper, flip and peel off the silicone mat.

Spread apricot jam over the first layer of biscuit.

For the mousse, beat the egg yolk mixture with cooked sugar on high, add melted gelatin and beat 10 minutes on high to a sabayon.

Mix a couple of tablespoons of whipped cream into the melted dark chocolate, then the sabayon and the remaining whipped cream.

Layer chocolate mousse and biscuit, repeating twice, keeping the cake even without a frame; make the top layer thinner, smooth the edges and freeze.

For the glaze, make a ganache of melted chocolate and hot heavy cream; separately cook sugar with cocoa powder, boil briefly and add the creme fraiche.

Off the heat, combine the ganache and chocolate syrup and cool to 113F (45C).

Trim the frozen cake and glaze it.