01 - Preheat a large nonstick skillet or griddle over medium-high heat until evenly hot.
02 - Divide ground beef into 4 equal portions and shape into loose balls without overworking.
03 - Place a beef ball onto one half of each tortilla. Season evenly with salt, pepper, garlic powder, and smoked paprika.
04 - Using a spatula or parchment paper with a heavy pan, smash each beef ball thinly and evenly onto the tortilla surface.
05 - Sprinkle a generous amount of shredded cheddar cheese over each smashed beef patty.
06 - Fold each tortilla over to form a half-moon shape, pressing gently to seal.
07 - Add 1/2 tbsp butter to the skillet. Place quesadillas in the pan, cooking in batches if necessary. Cook 2-3 minutes until golden and crisp, adding remaining butter as needed.
08 - Carefully flip each quesadilla and cook another 2-3 minutes until the second side is golden and crisp, and beef is cooked through.
09 - Remove quesadillas from skillet and let rest for 1 minute to set.
10 - Gently open each quesadilla and layer with lettuce, tomato, onion, pickles, and a spoonful of burger sauce.
11 - Close quesadillas and slice into wedges. Serve immediately while hot and crispy.