Preheat your oven to 350°F (175°C).

Brown the ground beef with the chopped onion in a skillet over medium heat. Cook until the beef is fully browned and the onion is translucent, about 5-7 minutes, then drain any excess fat.

Mix together the browned beef, mixed vegetables, cream of mushroom soup, and sliced potatoes in a large mixing bowl. Stir well to combine all the ingredients.

Season generously with salt and pepper to taste.

Transfer the mixture to a greased baking dish, spreading it out evenly.

Cover the dish with foil and bake in the preheated oven for 45 minutes.

Uncover the casserole and sprinkle shredded cheddar cheese on top. Bake for an additional 15 minutes until the cheese melts and is bubbly.

Serve warm and enjoy!