Coarsely chop the couverture and melt with butter over a warm water bath. Leave to cool a little. In the meantime chop the nuts coarsely. Peel and quarter pears, cut out the core. Cut quarter into slices.
Beat the eggs, salt and 300 g sugar with the whisk of the hand mixer. Stir in the crème fraîche and nut nougat cream. Allow the butter and chocolate mixture to shrink and stir in. Mix flour, cocoa and baking powder and stir in.
Fold in the nuts. Put the dough into a greased grease pan of the oven (39 x 32 cm), smooth it down and cover with pear wedges. Sprinkle with 50 g sugar. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for about 25 minutes.
Remove from the oven, place on a cake rack and allow to cool.