Heat 1 tablespoon olive oil in a large skillet over medium heat. Add 1 pound of lean ground beef, breaking it up as it cooks, until browned, about 5 - 7 minutes. Ensure that no pink remains in the beef before draining any excess grease and setting it aside to cool slightly.
In a small bowl, combine ½ cup mayonnaise, 2 tablespoons sweet pickle relish, 2 tablespoons yellow mustard, 1 tablespoon ketchup, 1 teaspoon white vinegar, ½ teaspoon onion powder, ¼ teaspoon paprika, and ¼ teaspoon salt. Mix well and add 1 teaspoon of water; adjust with more water if necessary until you reach your desired dressing consistency.
In a large bowl, add 5 cups of chopped romaine lettuce, along with 2 chopped roma tomatoes, ¾ cup grated cheddar cheese, ½ cup sliced pickles, and ⅓ cup sliced red onion.
Drizzle your prepared dressing over the salad ingredients in the bowl. Toss gently but thoroughly to ensure everything is well coated with that delicious copycat Big Mac sauce.
Sprinkle 1 tablespoon of sesame seeds on top as an elegant finishing touch before serving your salad immediately for optimal freshness.