Peel the onions, peel the potatoes, peel the meat sausage and do not dice too finely.
Melt the margarine in a saucepan, fry the onion, add the potato cubes and fry as well. Add the frozen Brussels sprouts and the broth and simmer until the Brussels sprouts are barely done, which takes about 20 minutes.
Stir in the pizza tomatoes and the sausage cubes and heat gently. Mix the mustard with the cream and stir into the no longer boiling soup.
If you like, you can also add diced carrots and parsnips at the beginning.