Line a baking tray (approx. 35 x 40 cm) with baking paper. Break chocolate into pieces for the chocolate cream. Bring the cream to the boil, remove from the stove. Dissolve the chocolate in it while stirring. Let it cool down for about 3 hours, then put it in a cool place for about 1 hour.
Separate eggs. Beat the egg whites and 1 pinch of salt until stiff, adding vanilla sugar and sugar. Beat the egg yolks separately. Mix flour, starch, 25 g cocoa and baking powder, sieve onto the egg foam and fold in.
Spread on the baking tray. Bake in the preheated oven (electric cooker: 200 °C/circulating air: 175 °C/gas: see manufacturer) for approx. 12 minutes.
Remove from the oven and let it rest for about 3 minutes. Turn the sponge onto a damp tea towel and remove the baking paper. Let it cool down. Sprinkle the sponge cake with liqueur. Stir the jam until smooth and spread it on the sponge cake.
Leave to soak for about 2 hours.
Cut 12 circles (each approx. 8 cm Ø) close together from the sponge cake plate using a dessert ring (or glass), cleaning the dessert ring from time to time. (Use the sponge cake leftovers for other purposes).
Whip the chocolate cream until creamy (approx. 30 seconds). Pour into a piping bag with a perforated spout (14 mm Ø) and spray small tuffs onto the 12 tartlets, pulling the spout slightly upwards while spraying.
Chill the tartlets for about 30 minutes. Dust with a little cocoa shortly before serving.