Preheat about a tablespoon of olive oil in a skillet over medium heat. Halve your onion and then slice it thinly and slice your pepper into thin slices.
Add the pepper and onion to your preheated skillet
In a separate skillet, heat about 2 tablespoons of EVOO over medium heat. Sprinkle both sides of the chicken breast liberally with the fajita spice rub. Add the chicken breasts to the pan.
Cook the chicken breasts about 5 minutes per side or until it is cooked through. You should have a beautiful dark brown crust on the outside.
Meanwhile, your onion and pepper should be sauteing nicely in your other skillet. Keep stirring them until the onion is caramelized and both the peppers and onions are golden brown.
When the chicken is done cooking, remove it from the pan and transfer it to a cutting board. Let it rest. That may sound silly but it is very important to let cooked meat rest for about 5 minutes after removing it from the pan. This allows the meat to finish cooking on the inside and letting it rest will retain all of the yummy juices on the inside. So after it has rested, slice it into slices or chunks, whatever you want.
So now your ingredients should all be ready to go and you should be ready to start building your quesadilla. Before you start the first one, preheat a skillet to medium heat and add about 1/2 tablespoon of butter. Each time you cook a quesadilla, you will want to add about a 1/2 tablespoon of butter.
Start constructing your quesadilla. First take a plain tortilla, add the cheese, chicken and sauteed vegetables to one side of it. Fold it over and add it to your pan. You should be able to start construction on your next one and finish it by the time this one is finished and keep the cycle going until they’re all finished.
Cook it for about 3-4 minutes or until it is golden brown and then using a spatula, flip it over so the other side can get pretty and golden.
Once it is finished, remove it from the skillet and transfer it to a clean cutting board where you can slice it. Then repeat the process until they’re all finished and ready to eat!