Clean the mussels. Chop the onions, leeks and carrots and sauté with the oregano, chilli and bay leaf. Raise the temperature and add the tomato paste and garlic. After about 5 minutes, deglaze with the wine. When it starts to simmer, add the stock.
When everything cooks vigorously, add the drained mussels. Let boil for 10 minutes, stir 1-2 times in between. Shortly before the end, season with salt and pepper.