01 - Combine ground beef with kosher salt, black pepper, garlic powder, and onion powder in a bowl. Mix gently until evenly distributed, then form into 8 equal balls.
02 - Place a large skillet or griddle over medium-high heat and allow it to come to temperature.
03 - Place 2 beef balls on the hot skillet. Using a sturdy spatula, press down firmly to smash each ball into a thin patty approximately the diameter of your tortillas. Cook for 1-2 minutes until deeply browned, then flip and cook another 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. Sprinkle 1/4 cup cheddar and 1/8 cup mozzarella over one half. Place a cooked smashburger patty on top, then add pickles, red onion, and a drizzle of ketchup, mustard, and mayonnaise. Top with shredded lettuce. Fold the tortilla in half to enclose the filling.
06 - Melt a small amount of butter in the skillet. Place assembled quesadilla in the pan and cook for 2-3 minutes per side, pressing gently with a spatula, until tortilla is golden brown and cheese is fully melted. Repeat with remaining quesadillas, adding more butter as needed.
07 - Cut each quesadilla into halves or quarters and serve immediately while hot.