Clean the mushrooms and cut them in half or into quarters, depending on their size. Peel and dice the shallots and garlic. Finely chop the leek and carrots. Heat the oil in a saucepan and sear the mushrooms. Set aside, heat a little oil in the saucepan and sear the vegetables. Stir in the tomato purée and flour, deglaze with wine and simmer for 3 minutes. Add the soup, bay leaves, mushrooms and thyme. Cover and simmer for a further 20 minutes. Then remove the lid and simmer for another 20 minutes. Season to taste with salt and pepper.