Heat a large skillet over medium-high heat, add ground beef, season with salt and pepper, and cook for 5–7 minutes until evenly browned, stirring occasionally. Drain any excess fat.

In a small bowl, whisk together mayonnaise, ketchup, yellow mustard, sweet pickle relish, garlic powder, and white vinegar until smooth and well combined.

Roughly chop romaine lettuce into bite-sized pieces, dice onions and pickles, and slice tomatoes.

Divide lettuce between bowls, top with warm beef, drizzle special sauce evenly, sprinkle shredded cheddar cheese, diced onions, and pickles.

Finish each bowl with sesame seeds and chopped parsley, then serve immediately.