Grease a coated pan with oil. Before heating, add a tortilla to the pan and sprinkle thickly with cheese and ham. Brush a second tortilla generously with salsa and place the coated side on the cheese and ham tortilla.
Place the pan on the stove and fry over medium heat until the cheese has melted and the lower tortilla is golden brown. Place a heat-resistant plate on the pan, press firmly with one hand and quickly turn the pan carefully. Then slide the turned tortilla back into the pan and fry it on the other side until golden brown.
Do the same with the rest of the tortillas. Serve with sour cream.
For a vegetarian version, instead of the ham, use sliced mushrooms marinated in olive oil with a crushed clove of garlic. Fresh spinach steamed in olive oil and garlic also tastes very good.