01 -
Cook ground beef and chopped onion in a large skillet over medium heat, stirring and breaking up the beef until fully browned and no pink remains, about 10 minutes. Drain excess fat.
02 -
Transfer cooked beef and onion to a large bowl. Add frozen mixed vegetables, diced potatoes, cream of mushroom soup, kosher salt, and black pepper. Stir thoroughly to evenly coat all ingredients.
03 -
Spread the mixture evenly into a greased casserole dish, flattening the top with a spatula for uniform baking.
04 -
Cover tightly with foil and bake in a preheated oven at 350°F for 45 minutes to ensure vegetables and potatoes are tender and flavors meld.
05 -
Remove foil, sprinkle shredded cheese evenly over the top, and bake uncovered for an additional 15 minutes until cheese is melted and bubbly.
06 -
Allow casserole to rest for 5 to 10 minutes after baking to firm up before serving.