Cream butter, 1 pinch of salt and sugar with the whisk of the hand mixer. Stir in the eggs one by one. Mix flour and baking powder. Alternately stir in milk and flour mixture by the spoonful.
Cut the dough in half. Mix one half of the dough with cocoa.
Place the cherries in a sieve and drain. Pour light-coloured dough into a greased box form (11 x 30 cm; 1.75 litres capacity), dust with flour. Spread cherries on top. Pour chocolate dough on top, swirl lightly with a fork and bake in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see
manufacturer) bake for about 50 minutes. Take out, let cool down for about 30 minutes. Carefully turn out of the tin and let it cool down.
Warm the jam in a pot and let it cool down slightly. Spread the jam over the cake. Heat the cream in a pot. Chop the couverture and melt in the cream while stirring. Pour into a bowl and allow to cool.
When the chocolate begins to set slightly, whisk vigorously with a whisk. Spread the chocolate mixture loosely over the cake. Chill the cake for about 30 minutes. Cut into pieces and serve.