Place ground beef and diced onion into a large skillet over medium-high heat. Season generously with salt, pepper, and paprika. Cook until the beef is thoroughly browned and no longer pink, breaking it up into small pieces as it cooks. Add the minced garlic and cook for another minute until fragrant. Drain any excess fat from the skillet and set the cooked meat mixture aside.
Step 3: Make the Creamy Sauce
In a mixing bowl, whisk together the condensed cream of mushroom soup, evaporated milk, and sour cream until smooth and well combined. Taste and adjust seasoning if needed. This creamy sauce is what binds all the layers together and creates that irresistible, gooey texture.
Step 4: Layer the Casserole
In your prepared baking dish, arrange a single layer of sliced potatoes on the bottom. Season lightly with salt and pepper. Spread about one-third of the cooked beef and onion mixture over the potato layer. Sprinkle about one-quarter of the shredded cheddar cheese over the beef. Repeat the layers — potatoes, beef, cheese — until all ingredients are used, finishing with a final layer of potatoes on top. Pour the creamy soup mixture evenly over the entire casserole, making sure it seeps down into all the layers.
Step 5: Bake Covered
Cover the baking dish tightly with aluminum foil and place in the preheated oven. Bake covered for 60–70 minutes, or until the potatoes are fork-tender. Check doneness by inserting a fork or skewer into the center — it should slide through the potato layers without resistance.
Step 6: Add Cheese and Finish
Remove the foil and sprinkle the remaining shredded cheddar cheese generously over the top of the casserole. Return to the oven uncovered and bake for an additional 10–15 minutes, or until the cheese is fully melted, bubbly, and lightly golden on top.
