Drain, wash, and stuff with a force-meat of crumbs and chopped fat pork, seasoned with onion-juice, salt, and pepper. Prepare the usual bed of vegetables - minced carrot, onion, celery, and parsley. Lay the pigeons upon it; add a cupful of stock, or of butter and water, cover and cook gently one hour, or until tender. Dish the birds and keep hot; rub the gravy through a colander into a saucepan, season to taste, add a dozen fresh mushrooms cut into small pieces, simmer five minutes, thicken with a tablespoonful of brown roux, boil up and pour over the pigeons.