This mashed potato casserole is creamy, cheesy, and topped with a golden, crunchy layer. It's perfect for family dinners, holidays, or anytime you want a cozy side that can double as a main. 👇👇

Why I Love This Recipe
- Creamy mashed potatoes with a cheesy, golden topping
- Family-friendly and feeds a crowd
- Simple pantry ingredients
- Works as a main or side (great leftovers)
- Make-ahead friendly for busy weeks and holidays
What Makes a Great Mashed Potato Casserole
- Use starchy potatoes like russet or Yukon gold for fluff and creaminess
- Remove excess moisture for a richer mash
- Add sour cream or cream cheese to help the dish reheat moist
- A crunchy topping (panko crumbs, bacon bits, or fried onions) adds texture
Next up - Recipe ingredients are below 👇👇

Ingredients
- 4 lb russet potatoes (or Yukon gold, peeled and cubed)
- 1 tsp salt
- 1 tsp garlic powder
- ½ tsp onion powder
- ¼ tsp black pepper
- ¾ cup whole milk
- ½ cup unsalted butter
- ½ cup sour cream (full fat)
- 4 oz mozzarella, shredded
- 4 oz cheddar, shredded
- 1 cup Italian panko breadcrumbs
- 2 green onions, thinly sliced
Optional:
- 4 slices cooked bacon, chopped
- ½ cup crispy fried onions
Step-By-Step Instructions 👇👇

STEP 1: Preheat Oven
Preheat to 400°F. Grease a 9×13-inch baking dish with butter.
STEP 2: Boil Potatoes
Peel 4 lbs russet potatoes and cut into 1-inch cubes. Add to a large pot, cover with cold water, and stir in 1 tsp salt. Boil 15 minutes, or until fork-tender.
STEP 3: Drain & Mash
Drain well. Return to a large bowl and mash until smooth (no large lumps).

STEP 4: Mix In Dairy & Seasonings
Stir in ¾ cup whole milk, ½ cup unsalted butter, ½ cup sour cream, 1 tsp garlic powder, ½ tsp onion powder, and ¼ tsp black pepper until creamy.

STEP 5: Transfer & Add Topping
Spread potatoes evenly in the baking dish. In a bowl, combine 4 oz mozzarella, 4 oz cheddar, and 1 cup Italian panko breadcrumbs. Sprinkle evenly over the potatoes.
STEP 6: Bake & Serve
Bake 30 minutes, until golden and the cheese is melted. Top with 2 sliced green onions. Rest 5 minutes, then serve.

Recipe Tips
- Use starchy potatoes (russets) for fluffy, creamy mash.
- Start in cold water so potatoes cook evenly.
- Mash by hand or with a ricer-don't overmix or they can turn gluey.
- Make ahead: assemble, cover, refrigerate; bake when ready.
- Broil 1-2 minutes at the end for extra crisp topping.
Variations and Substitutions
- Cheese swaps: Gruyère, fontina, smoked provolone
- Toppings: mix panko with bacon, fried onions, or herbs
- Butter alternative: Use plant-based margarine if needed
- Milk options: Whole milk, half-and-half, or non-dairy milk
- Mix-ins: Fold in garlic sautéed spinach, roasted garlic, or cooked bacon
How to Make Ahead & Reheat
- Assemble the casserole, cover, refrigerate 1-2 days before baking
- Let it come to room temperature before baking
- Reheat leftovers in the oven or toaster oven to keep topping crisp
- Microwave is okay, but add splash of milk to loosen the mash
How To Store Leftovers
- Fridge: Store covered 4-5 days.
- Reheat: Oven or toaster oven for a crisp top; microwave for quick heat.
- Freeze: Can freeze after baking (topping softens slightly).
Serving Suggestions
These pair well with grilled meats, chicken, roast turkey, or meatloaf. Use as a cozy main with sautéed green beans. Add roasted vegetables or a crisp salad to balance richness.
Serve with gravy, herbed butter, or a drizzle of olive oil.

FAQs
It's meant as a side, but loaded versions with bacon or meat make it hearty enough for a main.
You can, but freshly shredded cheese melts better and gives richer texture.
Yes. Assemble unbaked 24-48 hours in advance and bake later.
It removes excess starch that can cause gummy texture when cooked.
Yes, non-dairy milk or cream work. Use unsweetened versions and adjust richness.

Ingredients
- 4 lb russet potatoes - about 7-8 medium to large, before peeling
- 1 tsp salt
- 1 tsp garlic powder
- ½ tsp onion powder
- ¼ tsp black pepper
- ¾ cup whole milk
- ½ cup unsalted butter
- ½ cup sour cream - full fat
- 4 oz mozzarella - shredded
- 4 oz cheddar - shredded
- 1 cup Italian panko breadcrumbs
- 2 green onions - thinly sliced
Instructions
- Preheat oven to 400°F. Grease a 9×13-inch baking dish with butter.
- Peel potatoes, cut into 1-inch cubes, and boil with 1 tsp salt for 15 minutes or until fork-tender.
- Drain well. Mash until smooth.
- Stir in milk, butter, sour cream, garlic powder, onion powder, and black pepper until creamy.
- Spread into baking dish. Top with mozzarella, cheddar, and breadcrumbs.
- Bake 30 minutes, until golden and melted. Top with green onions and serve.
Notes
- Use starchy potatoes (russets) for fluffy, creamy mash.
- Start in cold water so potatoes cook evenly.
- Mash by hand or with a ricer-don't overmix or they can turn gluey.
- Broil 1-2 minutes at the end for extra crisp topping.
Nutrition
Nutrition info is auto-calculated and meant to be an approximation only.







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