Peel and pit the avocadoes. Use a spoon to remove the flesh from the avocadoes and place it in a bowl. Work it with a potato masher until it is the desired consistency. Add the jalapeno pepper, tomato, white onion, coriander and lime juice. Add salt and pepper and stir well. Set aside.
Spread out the tortillas on a work surface. Place approximately 60 ml (1/4 cup) of the guacamole on half of each tortilla. Close the tortillas and press lightly.
Using two non-stick frying pans, cook the quesadillas for around 3 minutes on each side over medium-low heat or until the cheese has melted. Serve immediately.