01 -
Wash and peel the potatoes; cut into thick fries.
02 -
Heat vegetable oil in a pot to 350°F (175°C). Fry the potatoes in batches until golden brown and crispy.
03 -
While fries cook, mix mayonnaise, ketchup, relish, and mustard in a bowl.
04 -
In another pan, sauté chopped onion in butter until caramelized (5-7 minutes).
05 -
Once fries are done, layer on a plate; drizzle with sauce, add cheese, and top with grilled onions.
06 -
Serve immediately while hot.