Onion: Grate the onion using the large holes of a grater to get 1 tablespoon for the sauce. Finely dice the rest (about 1 cup) for the beef.
Fries: Prepare fries according to package directions in the oven or air fryer.
Sauce: In a small bowl, mix together mayo, ketchup, relish, paprika, and the grated onion. Add 1/4 teaspoon salt (or to taste). Stir until smooth and chill until ready to use.
Beef: Heat a large cast-iron pan over medium-high heat. Add olive oil and the diced onion. Sauté for 4–5 minutes or until golden. Move the onion to the edges and add the beef to the center. Increase heat to high and sear for about 1 minute per side, then crumble and brown the beef. Season with garlic powder, paprika, onion powder, beef bouillon, salt (1/2 tsp), and pepper (1/4 tsp). Cook until beef is deeply browned and most of the fat has cooked off. Drain excess grease and remove from heat. Stir in Worcestershire sauce and adjust seasoning if needed.
Assemble: Divide fries and beef evenly among 4 bowls. Add your favorite toppings and drizzle with sauce. Sprinkle with sesame seeds and serve right away.
Notes
Note 1: I love using shredded iceberg lettuce, diced dill pickles, halved cherry tomatoes, thinly sliced red onion, sesame seeds, and shredded cheese.Nutrition Note: Calories do not include the toppings, as those will vary.Storage: Keep the lettuce and toppings in one container, the beef in another, and the sauce in another small container. Warm the beef before assembling. Best eaten within 3–4 days.