Cook the pasta according to package instructions.
In a large skillet, brown the ground beef over medium heat.
In a large mixing bowl, combine the cooked pasta, browned beef, pickles, cheese, and onion.
In a separate bowl, whisk together mayonnaise, mustard, ketchup, vinegar, salt, and pepper to create the dressing.
Pour the dressing over the pasta mixture and toss until evenly coated.
Gently fold in the shredded lettuce just before serving.
Taste and adjust seasoning as needed.
Refrigerate the salad for at least 30 minutes before serving.