Lay the bacon in a frying-pan and cook it until it is evenly crisp. Lift the bacon out with a slotted spoon and put it aside to cool (before crumbling it). Gently sauté the onion in the bacon fat. When the onion is soft but not browned, transfer it to a medium-sized saucepan. Stir in the breadcrumbs and add the beans and chicken stock. Season with salt and pepper and half a