Instructions:

1. Preheat the oven:
   Set oven to 375°F (190°C). Fit the pie crust into a 9-inch pie dish and set aside.
2. Brown the beef:
   In a skillet over medium heat, cook ground beef and onion until the beef is browned and onions are tender, about 7–9 minutes. Drain excess grease.
3. Add flavor:
   Stir in garlic, ketchup, mustard, salt, and pepper. Cook for 1–2 minutes, then remove from heat.
4. Layer the filling:
   Spoon the beef mixture evenly into the pie crust. Top with cheddar and mozzarella cheeses.
5. Make the batter:
   Whisk together eggs, milk, and flour in a small bowl until smooth. Pour over the meat and cheese layers.
6. Bake:
   Bake for 25–30 minutes, or until golden and set in the center. Allow to cool for 5–10 minutes before slicing.
7. Serve:
   Serve warm. Optionally garnish with pickles, chopped tomatoes, or serve alongside a fresh green salad.

Variations:

• Add cooked, crumbled bacon to the beef mixture for a bacon cheeseburger version.
• Swap ketchup and mustard for BBQ sauce for a smoky twist.
• Use pepper jack cheese for a spicy kick.

Tips:

• If using frozen pie crust, let it thaw before adding the filling to avoid sogginess.
• For a firmer base, pre-bake the crust for 5–7 minutes before adding the filling.
• Store leftovers covered in the refrigerator for up to 3 days and reheat in the oven for best texture.