Preheat oven to 200 degrees Fahrenheit (to keep quesadillas warm while cooking batches).

Meanwhile, heat olive oil in a large non-stick frying pan over medium heat. Add ground beef, chili powder, chipotle pepper, oregano, cumin, garlic powder, onion powder, salt, black pepper, and cayenne pepper (if using). Cook until ground beef is fully cooked through, about 8 to 10 minutes.

Stir in tomato paste and beef stock/broth and cook for 1 to 2 minutes more. Remove beef from the pan and place into a bowl. If there is any excess grease, drain/remove.

Distribute about 8 ounces (or 2 cups) of cheese among all tortillas on one side of them.

Distribute ground beef on top of cheese. Then sprinkle remaining 1 cup (or 4 ounces) of cheese on top of ground beef. Fold over each tortilla so it's a half-moon shape.

To cook quesadillas, heat about 2 teaspoons of vegetable oil in a large non-stick frying pan over medium-low heat.

Place two quesadillas in the pan. Cook quesadillas for about 2 minutes on one side.

Carefully flip quesadillas to the other side and continue to cook for another 2 minutes or until they're golden brown and crispy on the outside and the cheese is melted inside.

Transfer cooked quesadillas to a sheet pan and place into your preheated oven to keep warm while you are continuing to cook the remaining quesadillas.

Once done, cut each quesadilla in half so you have 12 pieces. Great served with salsa, guacamole and/or sour cream. Enjoy!