Heat a large cast-iron skillet or griddle over medium-high heat.

Divide the ground beef into four equal 4-ounce portions. Form into loose balls and season generously with salt, black pepper, and garlic powder.

Place one beef ball onto the hot skillet. Immediately place a flour tortilla on top of the meat and press down very firmly using a burger press or heavy spatula, flattening the meat out to the edges of the tortilla.

Cook for 2 to 3 minutes until the beef is browned and crispy with a crust formed.

Flip the entire tortilla and beef patty over so the tortilla is now on the bottom.

Sprinkle 0.25 cup of cheddar and 0.25 cup of Monterey Jack cheese over the cooked beef. Add a spoonful of diced onions.

Fold the tortilla in half like a traditional taco and cook for another 1 to 2 minutes per side until the cheese is melted and the tortilla is golden brown and crispy.

Remove from the skillet, open slightly to add pickles and a drizzle of burger sauce, then serve immediately.