Make the sauce by whisking all the ingredients together in a small bowl until well combined. Set aside in the refrigerator until ready to use.
Brown the beef in a large nonstick pan set over medium-high heat, breaking it up with a spoon, until browned and cooked through with no pink. Drain off excess fat, then season with salt and black pepper. Allow it to cool slightly.
Divide the lettuce between salad bowls, then top evenly with ground beef, cheese, onions, pickles, and tomato. Drizzle the salad with the Big Mac sauce, garnish with sesame seeds, and serve.
Notes
Drain the meat after it is cooked through with no pink. Dry the lettuce after it is rinsed.
If you plan to store a portion of this low carb Big Mac Salad, it is recommended to store the dressing, cooked beef, and fresh ingredients in separate containers and assemble just before serving. For best results, prior to serving heat the cooked ground beef in a large skillet.
For an already assembled salad, store for up to one day in the refrigerator in an airtight container.
The copycat Big Mac Sauce can be made ahead of time and stored in the refrigerator in an airtight container for up to 3-5 days before serving.