Heat 1 tablespoon of the oil in a frying pan or small sauté pan. Add the onion, garlic, red pepper and celery and cook over a low heat, stirring occasionally, for 3–4 minutes.
Add the tomatoes, stock and soy sauce. Bring to the boil, then reduce the heat and simmer for about 15 minutes, or until the sauce begins to thicken. Add the mustard, beans and sausage and continue to cook for a further 10 minutes.
Mix the breadcrumbs, Parmesan and parsley together and sprinkle over the sausage mixture. Drizzle with the remaining oil. Place under a preheated moderate–hot grill for 2–3 minutes or until golden brown.