1. Prepare the Potatoes
Slice the potatoes into ⅛-inch rounds. Place them in a bowl of cold water to prevent browning while you prepare the remaining ingredients.
2. Preheat the Oven
Preheat your oven to 350°F (177°C). Lightly grease a 9×13-inch baking dish.
3. Cook the Beef Mixture
In a large skillet or Dutch oven over medium-high heat, cook the ground beef with the diced onion and garlic until the beef is browned and fully cooked. Drain excess grease if needed.
4. Make the Cream Sauce
In a medium bowl, whisk together the cream of mushroom soup, half-and-half, onion powder, salt, and pepper until smooth.
5. Assemble the Casserole
Drain the potatoes thoroughly.
Layer the casserole in this order:
- One-third of the potatoes
- One-third of the beef mixture
- ¾ cup shredded cheese
- One-third of the sauce
Repeat the layers two more times.
For the top layer, finish with the remaining sauce and sprinkle the remaining 1½ cups of cheese evenly over the casserole.
6. Bake
Cover tightly with aluminum foil and bake for 1 hour and 10 minutes.
Remove the foil and continue baking uncovered for 20 minutes, or until the cheese is melted, bubbly, and golden brown.
7. Rest Before Serving
Let the casserole rest for 10–15 minutes before slicing and serving. This helps the layers set and makes serving easier.
