Cook the meat. Cook the ground beef in a large skillet over medium high heat. After cooking for about 7 minutes add the diced onions, Worcestershire sauce, garlic powder, 1 teaspoon of salt, and ½ teaspoon of pepper. Continue to cook the ground beef for 3 minutes
Cream cheese. Add cream cheese to the ground beef and heat over medium low heat until the cream cheese has melted and coats the beef.
Add eggs. Scoop the ground beef mixture into baking dish. In a small bowl whisk together eggs, heavy cream, remaining 1 teaspoon of salt, and ½ teaspoon of pepper. Pour the mixture over the ground beef shaking the casserole dish so the egg mixture is evenly distributed.
Big Mac sauce. While the casserole bakes make your Big Mac sauce by whisking all of the ingredients together in a small bowl. When the casserole comes out of the oven drizzle it with the Big Mac sauce before serving.
Serve. Let rest for 15 minutes and then serve. You can serve it as is or cook some shredded cabbage and serve over the cabbage. You can also top it with your favorite burger toppings.