Preheat your oven to 350°F (175°C).
In a large skillet, heat the olive oil over medium heat. Add the chopped onion and sauté until translucent, about 3-4 minutes.
Add the ground beef to the skillet, breaking it apart with a spoon. Cook until browned, about 5-7 minutes. Drain any excess fat.
Stir in the frozen mixed vegetables, garlic powder, salt, and black pepper. Cook for an additional 3 minutes until the vegetables are warmed through.
In a large mixing bowl, combine the diced potatoes and the cream of mushroom soup. Mix well until the potatoes are fully coated.
In a casserole dish, layer the beef and vegetable mixture evenly over the bottom. Then, layer the potato mixture on top of the beef mixture.
Cover the casserole dish with aluminum foil and bake in the preheated oven for 30 minutes.
After 30 minutes, remove the foil and sprinkle the shredded cheddar cheese evenly on top. Bake uncovered for an additional 15 minutes, until the cheese is melted and the potatoes are tender.
Remove from the oven and let it cool for a few minutes before serving.
Serve warm and enjoy your hearty Hobo Casserole.