Put sugar and butter in a mixing bowl and whisk until creamy. Stir in the eggs one by one. Mix flour and baking powder, sieve on top and stir in. Mix the poppy seed filling with espresso powder, ground almonds, coffee liqueur and brown sugar in a bowl. Grease a box form and dust with a little flour. Spread 1/3 of the dough in the mould and put half of the coffee-poppy seed mixture in the middle as strips. Cover with another third of the dough and spread with the remaining coffee-poppy seed mixture.
Spread the remaining dough on top. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: stage 2) for about 1 hour. Leave to cool in the tin for 10 minutes, then turn out onto a cake rack and let it cool down. Melt the couverture and crème fraîche over a warm water bath. Cover the cake with the icing. Coarsely chop the mocha beans. Sprinkle cake with mocha beans and poppy seeds