In a large skillet over medium heat, add the ground beef and diced onion. Cook until the beef is browned and the onions are translucent, about 5-7 minutes. Drain any excess grease.

Add the ketchup, yellow mustard, mayonnaise, sweet relish, paprika, garlic powder, and black pepper to the skillet. Stir well to combine and allow the mixture to simmer for about 5 minutes.

While the mixture simmers, preheat your oven broiler. Place the hamburger buns on a baking sheet and toast them lightly under the broiler (about 1-2 minutes), keeping a close eye to prevent burning.

Once the meat mixture is heated through, place a slice of American cheese on top and cover the skillet to melt the cheese, about 2-3 minutes.

To assemble, place a generous spoonful of the beef mixture onto the bottom half of each toasted bun. Top with shredded lettuce and pickles, then place the top half of the bun over the fillings.

Serve immediately with your favorite sides.

For added flavor, consider adding other toppings like diced tomatoes or extra pickles.

If you prefer a spicier kick, consider adding some cayenne pepper or hot sauce to the meat mixture.

Store leftovers in an airtight container in the refrigerator for up to 3 days. Reheat in the skillet before serving.