Cook rendered giblets in hot stock or soup until just cooked, lift out and let cool briefly. Keep the stock. In the meantime, sauté the finely chopped onion in a little butter, dust with flour and add about 1/8 l of the reserved stock and the red wine. Let the liquid boil down and thicken it with blackberry jam and sponge cake crumbs. Add the coarsely chopped giblets, let them simmer for a short time, season with salt, pepper and liqueur and serve with slices of napkin dumplings or crusty French bread.