Sachertorte

Preheat the oven to 170°C. Line the bottom of a 24 cm springform pan with parchment paper, grease the sides with 10 g butter and dust with 10 g flour. Melt the chocolate over a water bath and let it cool slightly.

Beat 150 g softened butter with 100 g powdered sugar and the seeds of 1 vanilla pod until light and fluffy. Separate the yolks from the whites and mix 6 egg yolks into the butter mixture one at a time, then gradually add the melted chocolate.

Whisk 6 egg whites, gradually adding 100 g sugar, until stiff peaks form. Fold the egg whites into the chocolate mixture, sift 140 g flour over the top and gently fold in with a spatula, being careful not to deflate the whites.

Transfer the batter to the pan and bake on the middle rack: for the first 10–15 minutes, leave the oven door open a finger's width, then close it and bake for about 50 minutes more. The sponge is done when it springs back slightly to the touch.

Remove the cake, release the sides of the pan and carefully turn it out onto a wire rack. After 20 minutes, peel off the parchment paper, turn the cake back over and let it cool completely.

Slice the sponge horizontally in half. Warm 200 g apricot jam and stir until smooth; spread the jam over the cut sides of both halves, sandwich them together and coat the sides of the cake with jam as well.

For the glaze, bring 200 g sugar and 125 ml water to a boil and simmer for about 5 minutes. Remove the syrup from the heat, let it cool slightly, then gradually stir in 150 g chopped chocolate until you have a thick, pourable glaze.

Pour the still-warm glaze over the top of the cake in one motion and quickly smooth it out with a spatula. Let the cake set at room temperature for 3 hours, until the glaze becomes smooth and firm.

Cut the cake into slices and serve with 100 g unsweetened whipped cream.