This Loaded Mashed Potato Casserole is the ultimate comfort food side dish.

It takes classic mashed potatoes and elevates them with melted Colby Jack cheese, crispy bacon, and a touch of sour cream for extra creaminess.

Baked until bubbly and golden, this easy casserole is the perfect crowd-pleasing dish for holiday dinners, potlucks, or any time you want something cozy and indulgent.

Whether you’re pairing it with roast turkey, steak, or a casual weeknight meal, this cheesy mashed potato casserole is guaranteed to steal the show.

Why You’ll Love This Recipe

Creamy and fluffy mashed potatoes baked to perfection

Loaded with flavor from sour cream, butter, cheese, and bacon

Make-ahead friendly – Reheats beautifully

Great for feeding a crowd – Perfect holiday or potluck side

Customizable with different cheeses or mix-ins

Comfort food classic that never disappoints

What You’ll Need (Ingredient Highlights)

Russet potatoes – Starchy and ideal for creamy mashing

Whole milk – Adds moisture and smoothness

Unsalted butter – For rich, silky texture

Sour cream – Adds tang and lightness

Colby Jack cheese – Mild and melty; perfect for casseroles

Bacon – Crispy and salty topping

Green onions or chives – For freshness and color

Salt – Enhances the flavor of the potatoes

Pro Tips Before You Start

Cut potatoes evenly – For even cooking

Don’t overmix – Overbeating can make mashed potatoes gluey

Use freshly shredded cheese – It melts better than pre-shredded

Warm the milk and butter – Helps blend smoothly with the potatoes

Drain well – Excess water can make potatoes watery

How to Make Loaded Mashed Potato Casserole

Step 1: Boil the Potatoes

Preheat oven to 375°F.

Peel and cube 2½ lbs of russet potatoes, then place them in a large pot and cover with water.

Bring to a boil, then reduce heat to medium and season with 1 tsp salt.

Cook until fork-tender, then drain well.

Step 2: Make the Creamy Base

While the potatoes cook, heat ¾ cup milk and 8 Tbsp butter in a small saucepan over low heat until the butter melts.

Turn off the heat and stir in ¼ cup sour cream until fully combined.

Step 3: Mash the Potatoes

Mash the drained potatoes until smooth.

Slowly add the warm milk mixture, continuing to mash or beat until light and fluffy.

Transfer to a greased baking dish and spread evenly.

Step 4: Add Bacon and Cheese

Cook 8 oz chopped bacon in a skillet until crispy. Drain on paper towels.

Sprinkle the bacon over the mashed potatoes, followed by 8 oz shredded Colby Jack cheese.

Step 5: Bake the Casserole

Cover the casserole dish with foil and bake at 375°F for 25 minutes.

Remove the foil and bake for another 10 minutes, or until the cheese is melted and bubbly.

Garnish with chopped green onion or chives before serving.

What to Serve With Loaded Mashed Potato Casserole

Roast chicken or turkey – A classic holiday pairing

Grilled steak or pork chops – For a hearty, satisfying meal

Green beans or roasted Brussels sprouts – Adds balance

Gravy or mushroom sauce – Extra indulgence

Side salad – For something light and fresh

Variations & Substitutions

Use cheddar, mozzarella, or Monterey Jack – Instead of Colby Jack

Swap bacon for turkey bacon or pancetta

Add garlic or caramelized onions to the mash

Make it spicy – Mix in jalapeños or red pepper flakes

Add cream cheese – For extra richness

Storage & Reheating Tips

Fridge – Store leftovers in an airtight container for up to 4 days

Freezer – Freeze baked casserole (without toppings) for up to 1 month

Reheat – In oven at 350°F until warmed through or microwave individual servings

Make ahead – Assemble the night before and bake the next day

FAQs

Can I use other potatoes?
Yes, Yukon Gold also works well and gives a slightly buttery flavor.

Can I make this ahead of time?
Definitely—assemble fully and refrigerate, then bake before serving.

Can I leave out the bacon?
Yes, for a vegetarian version, simply omit or replace with veggie bacon or sautéed mushrooms.

Is this gluten-free?
Yes, all ingredients are naturally gluten-free—just check your bacon and cheese labels.

What size baking dish should I use?
A 9×13-inch dish works best for even baking and easy serving.

Can I double the recipe?
Yes! Double everything and bake in two dishes or a larger roasting pan.

Final Thoughts

This Loaded Mashed Potato Casserole is everything you love about mashed potatoes—plus bacon, cheese, and a creamy tang from sour cream.

It’s indulgent, easy to make, and guaranteed to be a hit at any dinner table.

Whether you’re feeding a crowd or just craving comfort food, this casserole brings the flavor every single time.