Wipe the skillet clean with a paper towel lightly. I didn't do it too much because I still wanted a little butter left in the skillet. Place one tortilla in the skillet and sprinkle in ¼ of the cheese, then add in the mushroom zucchini mixture (divide it in half), then top with another ¼ of the cheese. Place another tortilla on top and the first tortilla should be getting a little browned. You will need to press your spatula against the top tortilla to help it stick. Flip the quesadilla over. Allow the quesadilla to brown for 2-3 minutes.