Brown ground beef in a skillet and drain excess fat.

Add chopped onions to the skillet and cook until softened.

In the same skillet, combine water, beef bouillon granules, salt, and oatmeal.

Simmer the mixture for 10 minutes to thicken the sauce.

Transfer the meat mixture to the bottom of a casserole or baking dish.

Spread mashed potatoes evenly over the meat layer.

Brush the mashed potatoes with melted butter for added flavor and browning.

Sprinkle paprika over the potatoes for color and flavor.

Bake in a preheated oven at 325°F (160°C) for 30 minutes, or until golden brown.

Serve hot with gravy.