Heat a large non-stick pan or your trusty cast iron skillet over medium-high heat. Add a little bit of olive oil, just enough to coat the bottom.
Cook the ground beef until no pink remains, breaking it apart with a spatula. Stir in the tomato paste and a packet of taco seasoning, cooking for a few more minutes until the beef is well-coated. Leftover ground beef taco meat from previous meals works great too!
Add corn kernels, black beans, or any other mix-ins at this time and allow to cook another minute or two to heat through.
Place tortillas on a flat work surface. Divide cheese and add it to half of each tortilla. Top the cheese with the beef mixture evenly among half of each tortilla. If desired, throw in some of your favorite taco toppings.
Fold tortillas in half over the filling to create a half-moon shape.
Cook quesadillas in the hot pan, flipping once, until both sides are golden brown and the cheese melts into perfection.
Place quesadillas on a cutting board and allow to rest for a minute or two before cutting into triangle shapes. Serve hot, with a dollop of sour cream or a sprinkle of pico de gallo.
