For a complete meal, serve with warm bread or rolls and sliced tomatoes.
Melt butter in Dutch oven. Saute shallots until soft. Add stock, wine Madeira, and tomato paste. Stir until smooth. Add fish. Season with salt and pepper. Bring just to a boil, reduce heat, and simmer, partially covered, 20 minutes. Garnish with chopped parsley or dill.