Four large tortillas
Grated cheese - either mild or sharp cheddar, or Monterey Jack
Olive oil or grapeseed oil
Black olives, sliced
Fresh tomatoes, diced
Apple cider vinegar
Heat a large cast iron frying pan to medium high heat. Add a small amount of oil, about a teaspoon and spread around the bottom of the pan with a spatula (you could use butter as well). Take one large flour tortilla and place it in the pan. Flip the tortilla over a few times, 10 seconds between flips. When pockets of air begin to form within the tortilla, take a handful of grated cheese, sprinkle over the top of the tortilla, making sure that the cheese does not land on the pan itself. Add whatever additional ingredients you choose - green onion, sliced mushrooms, olives, tomatoes, etc. If you would like your quesadilla to be a chicken quesadilla, add some diced cooked chicken. Take care not to layer on the ingredients to thickly - this is a quesadilla, not a quiche.
Reduce the heat to low and cover the pan. The cast iron pan should be hot enough by now to have plenty of residual heat to melt the cheese and brown the tortilla. If the quesadilla begins to smoke too much, remove from the heat. After a minute, check to see if the cheese is melted. If not, return the cover and keep checking every minute until the cheese is melted. When the cheese is sufficiently melted, use a spatula to lift up one side of the quesadilla and flip over the other side, as if you were making an omelette. The tortilla should by now be browned slightly. If it is not browned, turn the heat up to high and flip the quesadilla over every 10 seconds or so until it gets browned. Remove from pan and cut into wedges.
To make the lettuce to accompany the quesadilla, thinly slice some iceberg lettuce. Sprinkle some cider vinegar on it and some salt.
Serve with the lettuce, salsa, sour cream, and guacamole.