For the Special Sauce: Add ingredients to a bowl then stir to combine. Can be made several days ahead of time.
For the Quesadillas: Add cooked ground beef to a mixing bowl then add ketchup and mustard to taste (I usually go with 2 parts ketchup to 1 part mustard). You'll want the mixture to be on the 'saucy' side vs dry.
Heat a large skillet or electric griddle over medium heat then spray with nonstick spray.
Place a tortilla in the bottom of the skillet then sprinkle on a thin layer of cheddar cheese followed by the ground beef mixture.
Add your desired toppings then sprinkle on another thin layer of cheese and place a tortilla on top.
Once the tortilla has browned on the bottom, flip the quesadilla then continue to cook until the second side has browned.
Transfer the quesadilla to a cooling rack to cool for 5 minutes then transfer to a cutting board and slice into wedges.
Serve with Special Sauce.
