Preheat the oven to 375°F (190°C) and prepare a 9-inch pie dish with the crust.

In a large skillet, brown the ground beef for 5-7 minutes, breaking it into small pieces. Drain the excess fat.

Sauté the diced onion in the same skillet for 3-5 minutes until translucent. Combine with the ground beef.

Season the beef and onion mixture with salt, pepper, garlic powder, Worcestershire sauce, and ketchup. Simmer for a minute before removing from heat.

In a mixing bowl, whisk together the eggs and milk. Add the beef and onion mixture along with half of the shredded cheese. Stir to combine.

Pour the filling into the prepared pie crust and sprinkle the remaining cheese on top. Add optional toppings if desired.

Bake the pie for 30-35 minutes until the filling is set and the cheese is bubbling and golden brown.

Let the pie cool for 5-10 minutes before slicing. Garnish with chopped parsley before serving.