1) heat the oil in a saucepan on a medium heat and add the onion, garlic and peppers and fry for 7-10 minutes. Then add the minced beef and fry together for about 10 minutes and then add the spices and mushrooms.
2) add the beef stock to the mince beef and cook on a low heat for 15-20 minutes.
3) warm through the tortillas in the microwave (ten seconds approx.) and then divide the mince between all the tortillas, sprinkle over half the cheese and roll up nice and tightly and line a rectangular oven dish with them.
4) spoon over the chopped tomatoes, then the rest of the grated cheese and tear the mozzarella ontop.
5) put under the grill for 10-15 minutes, they should be nice and golden by then and bubbling.