The potato skins split easily once a knife slides into the centers, and the warm russet flesh scoops out in soft, fluffy pieces. That’s the starting point for this loaded twice baked potato casserole with cheddar and sour cream: bake the potatoes whole, mash the insides with butter and sour cream, then bake the mixture again under a blanket of cheddar.
I keep the mash a little chunky rather than working it until it’s completely smooth. Russets turn gluey when they’re overmixed, and a few soft pieces give the casserole the familiar texture of a twice-baked potato. Crisp bacon and green onions go on after the casserole rests, so the topping stays distinct against the melted cheese and creamy potatoes.
Kitchen Note
Set the tablespoon of butter aside before adding the rest to the potatoes. Once the mash is in the bowl, that little bit is easy to overlook, and it’s what greases the baking dish.
Save this loaded twice baked potato casserole for a cozy dinner or a potluck: fluffy russets, sharp cheddar, sour cream, and crisp bacon.
Why This Potato Casserole Shouldn’t Be Whipped Smooth
Russets are prized for their fluffy, dry centers, but that same starch can turn pasty if you mash them too aggressively. For this casserole, the goal isn’t a perfectly smooth purée. Mash just until the butter, sour cream, milk, and seasonings come together, then fold in the cheddar while the potatoes still have a few soft lumps.
That texture matters once the casserole goes back into the oven. The second bake heats the filling and melts the cheese; it doesn’t need to cook the potatoes further or fix a mash that’s already been worked too hard. A hand masher gives you a little more control than an electric mixer, especially when the potatoes are still warm and tender.
There’s also a practical difference between these and a bowl of mashed potatoes: the filling is spread in a baking dish, topped with cheese, and finished with bacon and green onions after baking. Keeping the potatoes slightly chunky gives each serving enough body to hold its shape on the plate without losing that creamy, buttery center.
What Russets, Sour Cream, and Sharp Cheddar Each Bring
- Russet potatoes — Their dry, starchy flesh bakes up fluffy and makes a sturdy casserole filling. Scrub and dry them before baking, then pierce them several times so steam can escape. I wouldn’t swap in a waxy potato here; it won’t mash to the same light texture.
- Sour cream and whole milk — Sour cream brings a gentle tang that keeps the butter and cheese from tasting too rich, while milk loosens the mash. Use sour cream you enjoy eating on its own; there isn’t a like-for-like replacement among the other ingredients without changing the filling’s tang and consistency.
- Unsalted butter — Butter enriches the potato mixture, and the reserved tablespoon greases the baking dish. Keeping it unsalted lets the kosher salt season the filling without competing with the cheddar and bacon.
- Sharp cheddar — Its stronger flavor holds up against the potatoes and sour cream. Divide it before you start: most goes into the filling, and the rest melts over the top. A milder cheddar will work, but the cheese flavor will be gentler.
- Bacon and green onions — Chopped bacon cooks into crisp, salty pieces, while thinly sliced green onions add a fresh, savory finish. Drain the bacon well after cooking so excess grease doesn’t collect on the casserole.
From Oven-Baked Russets to a Cheesy Casserole
Bake the potatoes until a knife slides in easily
Heat the oven to 400°F, pierce the scrubbed, dried potatoes several times with a fork, and set them directly on the oven rack. Bake for 55 to 75 minutes, checking the centers with a knife; it should slide in easily without meeting a firm spot. If one potato is larger than the others, test it separately rather than assuming they’re all ready together. Let them cool for about 10 minutes before halving them lengthwise and scooping the flesh into a large bowl; discard the skins.
Mash while keeping a little texture
Add the remaining butter, sour cream, whole milk, garlic powder, kosher salt, and black pepper to the potato flesh. Mash until the ingredients are combined but the mixture still looks slightly chunky. If you keep beating after the lumps are gone, the russets can become sticky and dense. Fold in 1 1/2 cups of the cheddar at the end so it’s distributed through the filling.
Bake the filling under its cheddar top
Use the reserved butter to grease a 9×13-inch baking dish, then spread the potato mixture evenly inside. Reduce the oven to 375°F and sprinkle the remaining 1/2 cup cheddar over the surface. Bake for 20 to 25 minutes, until the casserole is hot throughout and the cheese has melted. The top should look glossy with melted cheese, not dry or browned hard.
Cook the bacon and finish after the rest
While the casserole bakes, cook the chopped bacon in a 12-inch skillet over medium heat for 8 to 12 minutes, stirring often, until browned and crisp. Transfer it to paper towels to drain. When the casserole comes out of the oven, let it rest for 10 minutes before scattering the bacon and green onions over the top. Adding them at the end keeps the green onions fresh and the bacon from getting buried in the soft potato filling.
Two Easy Ways to Adapt the Casserole
Make it vegetarian without losing the cheddar finish
Leave off the bacon and use sharp cheddar made with vegetarian rennet. The casserole keeps its creamy, cheesy center but loses the bacon’s smoky crunch; the green onions still add a fresh finish.
Serve it in the potato shells
For individual portions, scoop the baked potato flesh carefully and keep the empty skins intact instead of discarding them. Spoon the mixed filling back into the shells, top with the reserved cheddar, and bake until hot and melted. The shells make the portions more rustic and add a firmer edge around the creamy filling.
Storage and Reheating
- Refrigerator: Store leftovers in a covered container for 3 to 4 days. The potatoes will firm up as they chill, and the bacon topping will soften.
- Freezer: Freeze portions in airtight containers for up to 2 months. Thaw overnight in the refrigerator; the potatoes may be a little less fluffy and the bacon won’t stay crisp.
- Reheating: Reheat covered in a 350°F oven until the center reaches 165°F. Covering helps keep the potatoes from drying out; uncovering too early can leave the edges dry before the middle is hot.
Questions That Come Up When Making This Potato Casserole
Loaded Twice Baked Potato Casserole with Cheddar and Sour Cream
Ingredients
Equipment
Method
- Preheat the oven to 400°F.
- Pierce the potatoes several times with a fork and bake directly on the oven rack for 55 to 75 minutes, until a knife slides easily into the center.
- Let the potatoes cool for about 10 minutes.
- Halve the potatoes lengthwise and scoop the flesh into a large bowl; discard the skins.
- Set aside 1 tablespoon of the butter to grease the baking dish.
- Add the remaining 7 tablespoons butter, sour cream, milk, garlic powder, salt, and pepper to the potatoes, then mash until combined but still slightly chunky.
- Fold in 1 1/2 cups of the cheddar.
- Grease a 9x13-inch baking dish with the reserved butter and spread the potato mixture in it.
- Reduce the oven to 375°F and sprinkle the remaining 1/2 cup cheddar over the top.
- Bake for 20 to 25 minutes, until hot throughout and the cheese is melted.
- While the casserole bakes, cook the bacon in a 12-inch skillet over medium heat for 8 to 12 minutes, stirring often, until browned and crisp.
- Drain the bacon on paper towels.
- Let the casserole rest for 10 minutes.
- Scatter the bacon and green onions over the top.
