Drain the pears in a sieve. Roughly chop the chocolate. Melt the butter and chocolate in a small saucepan over low heat while stirring, remove from the heat. Coarsely chop nuts
Whisk eggs, vanilla sugar, salt and sugar with the whisk of the hand mixer for 2-3 minutes until creamy, stir in chocolate butter. Mix flour and baking powder, stir into the chocolate mixture, fold in 2/3 of the walnuts
Grease the fat pan of the oven (32 x 39 cm) well. Spread the dough on it and smooth it down. Cut the pear halves into a fan shape, spread them on the cake and sprinkle the remaining nuts on top. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for 20-25 minutes (the dough is then still very soft and juicy)
Remove the tray from the oven and let it cool on a cake rack for about 3 hours. Coarsely chop the chocolate coating, melt over a warm water bath, let it cool down for about 10 minutes. Pour the couverture into a freezer bag, cut off one corner. Spray thin lines on the cake, let it set for about 30 minutes in a cool place. Cut the cake into 24 pieces
waiting time approx. 3 1/2 hours