Preheat your oven to 350°F.

In a large skillet, heat the vegetable oil over medium heat. Add the chopped onions and cook until they are translucent.

Add the ground beef to the skillet and cook until it is browned and crumbled.

Season the beef mixture with salt and pepper to taste.

In a greased 9x13 inch baking dish, layer the sliced potatoes on the bottom.

Spread the beef mixture on top of the potatoes.

Pour the condensed tomato soup over the beef mixture.

Sprinkle the shredded cheddar cheese on top of the casserole.

Bake the casserole in the preheated oven for 30-40 minutes or until the cheese is melted and bubbly.

Remove the casserole from the oven and let it cool for a few minutes before serving.