Fold in about two-thirds of the shredded cheddar and two-thirds of the crumbled bacon, reserving the rest for the top. Taste and adjust seasoning with additional salt and pepper if needed.
Transfer the potato mixture to the prepared baking dish, spreading it into an even layer. Sprinkle the remaining cheddar and bacon evenly over the top.
Bake, uncovered, for 20–25 minutes, or until the cheese is melted, bubbling around the edges, and lightly golden in spots.
Let the casserole rest for about 5–10 minutes before serving. This brief cooling time helps the casserole set slightly, making it easier to scoop clean portions. Serve warm.
Because this recipe is built on just five core ingredients, it’s an excellent base for experimentation. If you’d like a bit of color and freshness, you can stir in sliced scallions or chives after baking; they won’t count against your 5-ingredient list if you think of them as a garnish rather than a component. For a smokier profile, swap half the cheddar for smoked cheddar or gouda. If you prefer a slightly lighter casserole, use half sour cream and half plain Greek yogurt; the tang remains, but the dish feels a touch less heavy. You can also treat this as a full main dish by folding in cooked, shredded chicken or diced ham along with the cheese and bacon. For make-ahead convenience, assemble the casserole up to the point of baking, cover, and refrigerate for up to 24 hours; when you’re ready to bake, add an extra 5–10 minutes to the oven time, watching for bubbling edges and melted cheese. Finally, if you enjoy a crisp top, run the casserole under the broiler for 2–3 minutes at the end of baking, keeping a close eye so the cheese browns without burning.
