Classic American Cheeseburger Pie

Preheat the oven to 400°F (204°C).
Grease a 9-inch glass pie plate with butter or vegetable oil for richer flavor.
In a large skillet, cook the chopped onion in butter or oil over medium heat until soft and translucent, about 3-4 minutes.
Add the ground beef to the skillet, season with salt, black pepper, and optional garlic powder. Cook until browned and no pink remains, about 8-10 minutes. Drain any excess fat.
Spread the cooked beef and onion mixture into the prepared pie plate. Top with 1 cup of the grated Cheddar cheese.
In a bowl, beat together Bisquick mix, milk, and eggs until smooth. Pour over the beef and cheese in the pie plate.
Bake for 25 minutes. Then, carefully remove the pie from the oven, lay the American cheese slices on top, and sprinkle the remaining cup of grated Cheddar cheese over it.
Return the pie to the oven and bake for an additional 5 minutes, or until the cheese on top is melted and bubbly, and a knife inserted in the center comes out clean.
Let the pie stand for 5 minutes before slicing and serving to allow the filling to set.

Prep Time: 15 minutes | Cooking Time: 30 minutes | Total Time: 45 minutes
Kcal: Adjusted for additional cheese (will be higher than 540 kcal) | Servings: 4