Preheat and Prep: Preheat your oven to 375°F (190°C). Lightly grease a 9x13-inch baking dish.

Season and Shape the Beef: In a large bowl, combine ground beef, garlic powder, onion powder, salt, and pepper. Mix well and form into 6 equal-sized patties.

Brown the Patties: Heat a skillet over medium heat. Brown the patties on both sides (they do not need to be fully cooked). Set aside.

Make the Gravy: In the same skillet, whisk together 1 cup of milk and flour until smooth. Gradually add the remaining milk while stirring constantly. Cook until the gravy thickens. Season with salt and pepper to taste.

Layer the Potatoes and Onions: Arrange half of the potato slices in the prepared baking dish. Top with half of the sliced onions. Place the browned hamburger patties over the onions, then layer with the remaining potatoes and onions.

Add the Gravy and Bake: Pour the gravy evenly over the potatoes and patties. Cover with aluminum foil and bake for 1 hour.

Add the Cheese and Finish Baking: Remove the foil, sprinkle shredded cheddar cheese on top, and bake uncovered for an additional 15 minutes, or until the cheese is melted and bubbly.

Serve and Enjoy: Let the bake cool slightly before serving. Enjoy warm!