Heat a large skillet over medium-high heat.
Add the ground beef and diced onion, breaking the meat apart as it cooks.
Season with garlic powder, onion powder, smoked paprika, salt, and black pepper.
Cook until the beef is browned and the onions are tender.
Drain excess grease if needed and set the mixture aside.
In a small bowl, whisk together mayonnaise, ketchup, mustard, pickle relish, and garlic powder to create the burger sauce.
Lay a tortilla flat on a clean surface.
Sprinkle cheddar and mozzarella cheese over half of the tortilla.
Add a layer of the cooked beef mixture.
Drizzle with a little burger sauce.
Fold the tortilla in half.
Melt butter in a large skillet over medium heat.
Cook each quesadilla for 2 to 3 minutes per side until golden brown and crispy.
Transfer to a cutting board and let rest briefly before slicing.
Serve warm with extra burger sauce and pickles.