For the chocolate cream, break 175 g chocolate into pieces. Heat the cream, take it off the stove and melt the chocolate in it. Pour into a bowl and place in a covered place for about 3 hours.
For the dough, grease 10 wells of a muffin tin (12 wells). Mix 250 g flour, cocoa and icing sugar in a bowl. Add 150 g butter in pieces and egg. Knead first with the dough hooks of the mixer, then with your hands briefly to a smooth dough.
Form the dough into a thick roll (approx. 7 cm Ø) and cut into 10 slices. Press each slice into a flat circle (approx. 11 cm Ø) with your hands on a floured work surface.
Place the muffin pan in the recesses of the muffin tin, press lightly on the bottom and edges, cut off any excess dough. Then chill for at least 1 hour.
Preheat oven (electric cooker: 200 °C/circulating air: 175 °C/gas: see manufacturer). Cut 10 squares (each approx. 14 x 14 cm) from baking paper. Place the paper squares on the dough in the troughs and add dried peas.
Pre-bake in the oven for about 20 minutes. Remove the paper together with the dried peas and continue baking for about 5 minutes. Allow to cool briefly, then carefully remove the dough bowls from the trays. Let them cool down.
For the icing, break 125 g chocolate into pieces. Carefully heat the double cream and chocolate in a pot while stirring, but do not boil! Stir until a smooth glaze is obtained.
Let it cool down.
Whip the cooled chocolate cream briefly with the whisks of the mixer. Pour into a piping bag without a spout, squirt into the pastry bowls and smooth down (or fill in with a spoon).
Spread the glaze over the tartlets, smooth it down and refrigerate for at least 1 hour. Remove from the fridge about 30 minutes before serving. Serve with semi-stiff whipped cream.