2 eggs, 100 g buckwheat flour, 130 g chestnut flour, 1/2 sachet of leavening powder with tartar and bicarbonate, 80 g of cane sugar, 2 tablespoons of bitter cocoa, 2 tablespoons of rum (or milk), 80 g of dark chocolate to 80% of cocoa, 50 grams of peeled and roasted hazelnuts.
Beat the whole eggs with the sugar until foamy. Add the sifted flour with the rising powder, cocoa, rum, coarsely chopped dark chocolate and hazelnuts. Form a loaf and place on a baking sheet covered with parchment paper. Bake in preheated oven at 180 degrees for 25-30 minutes. Once cooked, cut the loaf into slices and cook the biscuits in the oven for another 10 minutes. Let them cool and serve them with a good tea.