To Make The Sauce: In a bowl, combine all the sauce ingredients. Mix well until everything is fully combined. Cover and refrigerate for at least 30 minutes to allow the flavors to meld together.
To Make The Croutons: Preheat oven to 350°F (180°C). Using a large piping tip, cut out small circles from the hamburger buns. Alternatively, these can be chopped or torn.
Place the mini bun circles on a baking sheet and spray or lightly brush with oil. Bake for 7 minutes or until crispy. Alternatively, you can use an air fryer.
To Make The Salad: In a skillet over medium heat, cook the ground beef, breaking it up with a spatula, until browned. Season with salt, pepper, and garlic powder. Drain any excess fat and set aside to cool slightly.
Drizzle the chilled Big Mac sauce over the top. Toss the salad to combine all the ingredients and ensure everything is well coated with the sauce. Top with croutons if using, and serve immediately.