Chop half an onion very finely, brown it in butter, add the rabbit pieces and slightly brown them. Season with salt, pepper and add white wine. Once the wine has evaporated, ladle in the stock and cook gently. In the meantime, prepare the sauce: sauté the peppers, tomato and half onion in oil for about twenty minutes, then put the whole thing through a sieve. Pour the sauce over the rabbit adding also crushed pine nuts, and continue to cook for a few minutes.