01 - Combine ground beef with kosher salt, black pepper, garlic powder, and onion powder in a mixing bowl. Gently mix until just incorporated, then form into 8 equal balls.
02 - Place a large skillet or griddle over medium-high heat and allow it to preheat thoroughly.
03 - Add 2 beef balls to the hot skillet. Using a sturdy spatula, firmly press each ball flat to create thin patties matching the tortilla diameter. Cook 1-2 minutes until deeply browned, then flip and cook an additional 1-2 minutes until cooked through. Transfer to a plate and repeat with remaining beef.
04 - Wipe the skillet clean and reduce heat to medium.
05 - Lay a tortilla flat. Distribute 1/4 cup cheddar and 1/8 cup mozzarella over half the surface. Position a cooked patty on the cheese, then scatter pickles, red onion, and lettuce. Drizzle with ketchup, mustard, and mayonnaise. Fold the tortilla over to enclose the filling.
06 - Melt butter in the skillet. Cook quesadillas 2-3 minutes per side, applying gentle pressure with the spatula, until tortillas develop golden-brown color and cheese melts completely. Cook in batches as needed.
07 - Cut each quesadilla into halves or quarters. Serve immediately while hot and crispy.