1. Clean the tripe with water, cut them into small pieces and cook them in salt water during 20 minutes. Strain it and let it stand in cold water.
2. In a casserole with oil and 20g of butter, fry, over a gentle heat, the onion, celery, carrot and some leafs of basil (cut in thin). Add the white wine and let it evaporate.
3. Add the strained tripe and the tomatoes (without skin or seed and cut into pieces). Add salt and pepper and cook it during 15 minutes, adding some hot stock from time to time.
4. Divide the course into small individual casseroles, put some pieces of butter on the top of it and sprinkle with a lot of grated cheese. Cook au gratin during 10 minutes.