Cook the Beef: Heat a skillet over medium-high heat. Add ground beef and cook until browned, breaking it up with a spoon.
Season the Meat: Stir in chopped onion, yellow mustard, garlic powder, onion powder, salt, and black pepper. Cook for another 2-3 minutes until onions are soft. Drain any excess fat and set aside.
Prepare the Big Mac Sauce: In a small bowl, whisk together mayonnaise, ketchup, chopped pickles, pickle juice, garlic powder, onion powder, and paprika until smooth.
Assemble the Bowls: Divide shredded iceberg lettuce among four bowls. Top each with the cooked beef mixture.
Add Toppings: Sprinkle on shredded cheese, chopped pickles, diced tomatoes, and red onion.
Drizzle & Serve: Spoon the homemade Big Mac sauce over the top and enjoy immediately!