First clean the mussels, throw away those that have already been opened. Heat the olive oil in a large saucepan, peel and squeeze the garlic cloves. Roughly chop the parsley and sauté with the garlic. Peel and roughly chop the onion and add it as well.

Then put the mussels in dripping wet and cook for about 5 minutes until they have opened. Pour in white wine and broth, season with salt and pepper and cook for about 10 minutes.

Knead the butter with the flour, dissolve in the broth and stir until smooth. Use only the opened mussels, distribute on the plates, drizzle with the stock, sprinkle with chopped parsley and serve immediately hot.

Roasted white bread and lemon wedges are served with it.