Heat the olive oil in a large frying pan over a medium to high heat.
Spread one tablespoon of salsa on one of the tortillas, leaving about 2 centimetres around the edges without salsa. Repeat with the second tortilla.
Heap the grated cheese into the middle of the first tortilla.*
Place the second tortilla on top of the first tortilla, so that you have a giant tortilla sandwich. Press down so that the tortillas are "glued" together by the cheese and salsa.
Carefully transfer the tortilla sandwich to the frying pan. Fry for 3-4 minutes until the underside is browned. Using a spatula, flip it over the fry the other side for a further 3-4 minutes.
Slip your quesadilla out of the frying pan and on to a plate. Slice into 6 pieces and enjoy.
*If you want a more packed quesadilla, scatter a few of the following on top of your cheese:
green or black olives, sliced
sliced red onion
Fresh tomatoes, diced
Cooked chicken pieces