In a large mixing bowl, combine ground beef, salt, black pepper, smoked paprika, garlic powder, cayenne pepper, and Worcestershire sauce; mix until just combined.
Divide the mixture into four equal portions and form into thin patties.
Heat vegetable oil in a large skillet over medium-high heat and add the patties once hot.
Smash the patties with a spatula to ensure full contact with the skillet and cook until crispy on one side, about 3-4 minutes.
Flip patties and cook for another 2 minutes or until desired doneness; remove and drain on paper towels.
Wipe the skillet clean and return to medium heat; add butter to coat the skillet bottom.
Place one flour tortilla in the skillet and sprinkle with 1/4 cup shredded cheddar cheese.
Top with one cooked patty, diced red onion, sliced jalapeños, and another 1/4 cup cheddar cheese.
Fold the tortilla over to enclose the fillings and press gently to seal.
Cook the quesadilla for 2-3 minutes on each side until golden brown and cheese is melted.
Repeat with remaining tortillas and ingredients.
Slice quesadillas into wedges and serve with salsa, sour cream, and guacamole.