First prepare the filling. Melt the butter in a frying-pan. Add the onion and fry until it is soft. Stir in the meat and fry until it loses its pinkness. Remove the pan from the heat and transfer the mixture to a bowl. Stir in the remaining filling ingredients until they are thoroughly blended. Set aside.

Preheat the oven to moderate 180°C (Gas Mark 4, 350°F).

Brush a large frying-pan with some of the oil and heat over moderate heat. Holding a tortilla between your finger and thumb, dip it into the chilli sauce, shaking off any excess. Carefully arrange the tortilla in the hot frying-pan and fry for 30 seconds on each side. Using a spatula or tongs, transfer the cooked tortilla to a large plate. Spoon about a tablespoon of filling into the centre, and roll up Swiss (jelly) roll style. Arrange the roll in a large, greased baking dish. Keep hot while you cook and stuff the remaining tortillas in the same way.

When all the tortillas have been stuffed, pour the remaining sauce over them and sprinkle over the grated Parmesan. Put the dish into the oven and bake for 15 to 20 minutes, or until the sauce has browned and is bubbling. Remove from the oven and serve at once.