Name: Cheesy Bacon Mashed Potato Casserole Recipe
Prep time: 20 min
Cook time: 45 min
Total time: 1 h 5 min
Cuisine: American
Ingredients: 1.75kg / 3.5 lb potatoes (Sebago, Russet, Maris Piper, or King Edwards); 1 tbsp cooking/kosher salt (for cooking potatoes); 2/3 cup milk (preferably full fat/whole milk); 2/3 cup extra milk (for make-ahead option only); 75g / 5 tbsp unsalted butter, cut into 1cm / 1/2″ cubes; 1/2 cup sour cream (full fat preferred); 1 1/2 cups shredded mozzarella (tightly packed); 1 cup shredded Red Leicester, cheddar, or other flavored cheese (tightly packed); 1 tsp cooking/kosher salt (or to taste); 200g / 6 oz streaky bacon, chopped; 1/4 cup green onion, finely sliced

If you’re craving the ultimate comfort food side, I’ve got just the recipe to share with you. My Cheesy Bacon Mashed Potato Casserole Recipe is honestly one of my all-time favorites — it’s rich, creamy, loaded with melty cheese, and that crispy bacon on top? Game-changer. Whether you’re prepping for a family dinner or a holiday feast, this casserole brings everyone to the table with smiles and seconds (and sometimes thirds!). Stick with me, and I’ll walk you through everything so you nail it perfectly every time.

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Why You’ll Love This Recipe

Super creamy mashed potatoes: The secret combo of milk, butter, and sour cream makes the texture ultra-smooth and indulgent.
Cheese that melts just right: Using mozzarella and a sharper cheese means that golden, gooey top that’s impossible to resist.
Crispy bacon without extra oil: Cooking streaky bacon slowly in its own fat gives you that perfect crunch and flavor.
Make-ahead friendly: You can prep this casserole in advance and still get fantastic results that taste freshly made.

A white oval dish filled with mashed potatoes as the base layer, smooth and creamy with a pale yellow color. On top, a thick layer of melted bright orange cheese mixed with crisp, dark brown bits of bacon-like topping evenly spread. Scattered green onion rings add a fresh pop of green on the rich upper layer. A spoon is scooping into the dish, pulling up a string of melted cheese that stretches between the spoon and the remaining food. The dish rests on a white marbled surface, with a gray cloth nearby. Photo taken with an iphone --ar 4:5 --v 7

Ingredients You’ll Need

All the ingredients come together to create a perfect balance of flavors and textures — sturdy potatoes for fluffy mash, full-fat dairy for richness, and cheese and bacon for an irresistible topping. I recommend grabbing the best quality cheese you can find and fresh streaky bacon for that deep smoky flavor.

Potatoes: I love using Russet or Maris Piper since they mash so beautifully without getting gummy.
Salt (for cooking and seasoning): It’s key to seasoning your potatoes right — don’t skip salting the boiling water!
Milk: Full-fat milk works best for creaminess, but lite milk can work too if you’re watching calories.
Unsalted butter: Using butter gives richness and that silky smooth texture.
Sour cream (or yogurt): Adds a subtle tang and helps keep the mash creamy without heaviness.
Mozzarella cheese: Freshly shredded for best melt and stretch.
Red Leicester or Cheddar cheese: Pick one with good flavor and color to make the topping pop.
Bacon (streaky): Choose fatty bacon so it crisps up nicely without needing extra oil.
Green onion: For a fresh, mild bite sprinkled on top when serving.

Note: You’ll find the complete list of ingredients, along with their exact measurements, in the printable recipe card at the bottom of this post.

Variations

I’m all about making this casserole your own. Once you’ve nailed the base, feel free to experiment with different cheeses or add-ins. I’ve tried swapping sour cream for Greek yogurt or mixing in some herbs for a bit of brightness — each version turns out wonderful.

Cheese substitutions: I once used Gruyère instead of Red Leicester; it gave a lovely nutty depth, and my family went crazy for it.
Dairy-free option: Try non-dairy butter and milk alternatives, plus vegan cheese — it won’t be exactly the same, but still delicious.
Herb add-ins: Fresh thyme or chives mixed into the mash brighten the flavors beautifully.
Spicy kick: Adding a dash of smoked paprika or cayenne to the cheese topping is a surprise hit at dinner parties.

How to Make Cheesy Bacon Mashed Potato Casserole Recipe

Step 1: Cook the bacon perfectly

Start by placing your chopped streaky bacon in a cold non-stick frying pan — no need for oil! As the pan warms, the bacon will release its own fat. When you see that lovely bacon fat melting, turn the heat up to medium-high and stir frequently for about 3 minutes until the bacon turns golden and crispy. Then transfer it to paper towels to drain. That no-oil method is something I discovered and now always use — it gives you crispy bacon without the greasy mess.

Step 2: Prepare the potatoes

Peel your potatoes and cut them into 1-inch chunks. Placing them in a big pot, cover them with cold water so there’s about 4 inches above the potatoes, and add 1 tablespoon of salt. Bring that to a boil, then reduce to a rapid simmer (not a rolling boil) and cook until the potatoes are super soft — about 15 minutes. You want to be able to easily jab a fork and have the potato fall apart. Overcooking slightly is better than undercooking here.

Step 3: Mash and mix gently

Drain your potatoes really well, then put them back in the hot pot for a minute, shaking gently to help evaporate any excess moisture. This keeps the mash fluffy. Now add the milk (and the extra milk if you’re prepping ahead), cubed butter, sour cream, and 1 teaspoon salt. Use a hand masher to work everything together — avoid food processors or beaters because they make the potatoes gluey. I used to struggle with this, but swapping to a good ‘ol masher changed the game.

Step 4: Assemble and bake

Preheat your oven to 400°F (200°C). Transfer the mash into a 2-quart baking dish and smooth the top. Then sprinkle over the shredded cheeses and crispy bacon bits. Cover loosely with foil and bake:** 20 minutes if freshly made, or 35 minutes if you’re reheating a make-ahead casserole. After that, remove the foil and bake for another 10 minutes so the cheese bubbles and forms that irresistible golden crust.

Step 5: Garnish and serve

Once baked, sprinkle chopped green onions on top for a fresh, colorful finish. This casserole surprisingly stays warm for a good 20 minutes thanks to that cheesy cozy layer, so no rush to dive right in — but just a warning, it’s hard not to!

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Pro Tips for Making Cheesy Bacon Mashed Potato Casserole Recipe

Don’t overwork your mash: Using a potato masher instead of an electric mixer keeps the texture light and fluffy without turning gluey.
Shred your cheese fresh: Pre-shredded cheese won’t melt as well because it has anti-caking agents; I always shred mine right before assembly for the best melt.
Bring casserole to room temp: When reheating a make-ahead casserole, take it out of the fridge about 2 hours before baking so it warms evenly and stays moist.
Use streaky bacon only: It crisps up perfectly in its own fat; lean bacon needs oil and just doesn’t get the same flavor or texture.

How to Serve Cheesy Bacon Mashed Potato Casserole Recipe

The image shows a black bowl with a layered dish inside. The bottom layer is creamy mashed potato in white color, topped with melted orange cheese that is slightly stretchy. On top of the cheese, there are small crispy brown bits, possibly bacon or crispy onions, and a few green onion slices scattered for color. A silver spoon is inside the bowl, with some of the cheesy mixture lifted. Behind the bowl is a white baking dish with more of the same dish, showing melted cheese and crispy topping. Both containers sit on a soft gray cloth on a white marbled surface. Photo taken with an iphone --ar 4:5 --v 7

Garnishes

I actually love the simplicity of chopped green onions on top — they add a fresh pop of color and a mild savory bite that contrasts beautifully with the creamy richness. Sometimes I also sprinkle a little extra sharp cheddar just before serving if I’m feeling extra cheesy.

Side Dishes

This casserole is a stunner alongside roasted veggies like Brussels sprouts or green beans. I’ve also paired it with juicy grilled chicken or slow-cooked pot roast — the creamy potatoes soak up all those meaty juices perfectly.

Creative Ways to Present

For special occasions, I like to serve this cheesy bacon mashed potato casserole in individual ramekins, topped with extra crispy bacon and a sprig of fresh thyme — it instantly feels festive and makes every guest feel special. I also sometimes layer mashed potatoes with cheese and bacon in a trifle dish for a show-stopping presentation.

Make Ahead and Storage

Storing Leftovers

After enjoying this dish, I usually pop any leftovers into an airtight container and keep them in the fridge for up to 3 days. The casserole tastes great cold on Day 2 but the texture of the mash softens, so I recommend reheating for best experience.

Freezing

I haven’t personally frozen this casserole yet, but a colleague swears by freezing it after assembly, thawing overnight in the fridge, and baking as normal. If you try this, just be sure to cover it tightly to prevent freezer burn — I’ll update after testing it myself!

Reheating

To reheat leftovers, I cover the casserole loosely with foil and warm it in a 350°F (175°C) oven until heated through, about 20 minutes. Taking it out of the fridge a couple of hours before helps it warm evenly without drying out.

FAQs

Can I use instant mashed potatoes for this casserole?

While instant mashed potatoes offer convenience, this recipe shines best with real boiled potatoes for that creamy, homemade texture and flavor. The difference in richness and mouthfeel really stands out.
What if I don’t have full-fat sour cream?

You can substitute full-fat yogurt instead, which also adds a nice tang and creaminess. Just make sure it’s plain and unsweetened to keep the flavor balanced.
How do I prevent the mashed potatoes from becoming gluey?

The biggest mistake is using a food processor or blender. Stick to a hand masher and be gentle — overworking breaks down the potato cells too much, releasing starch that creates a gummy texture.
Can I prepare this casserole ahead of time?

Yes! You can assemble the casserole (except the green onions) and refrigerate it for up to 3 days before baking. Just remember to bring it to room temperature before cooking to ensure even baking.

Final Thoughts

I absolutely love how this Cheesy Bacon Mashed Potato Casserole Recipe never fails to impress. When I first made it, the combination of creamy potatoes, bubbling cheese, and crispy bacon elevated a simple side dish into something truly memorable. It’s one of those cozy recipes I always recommend to friends because it hits all the right notes without any fuss. Give it a try—you’ll see why it’s become a staple in my kitchen and among my family and friends!