Peel the onions and garlic and cut into very thin slices. Heat the margarine, sauté the vegetables while stirring and let simmer, covered, over a mild heat for 20 minutes. Stir occasionally. In doing so, it loses its sharpness and the typical aroma of the soup develops. Preheat the oven to 200 ° C. Pour in the wine and bring the whole thing to the boil, simmer openly for a few minutes, then stir in the broth. Bring the soup to the boil and then divide it into 4 soup cups. Roast toast and place a slice on top of the soup. Sprinkle with cheese and bake everything in the oven for 10 minutes on the middle rack.
If you want, you can also use dry white wine (the variant I prefer).