15-Minute Mashed Potato Casserole Recipe – Perfect Side Dish

Mashed potato casserole is the ultimate comfort food

What is Mashed Potato Casserole?

Traditional mashed potatoes are often a simple side dish made with boiled potatoes, butter, cream, salt, and pepper. Mashed potato casserole goes a step beyond by layering mashed potatoes with cheese, sour cream, and sometimes crunchy toppings like breadcrumbs or fried onions, then baking it to golden perfection. The casserole becomes creamy on the inside with a delightful crusty top.

Why You’ll Love This Recipe

• Easy to prepare and can be made ahead of time
• Rich, creamy texture with a cheesy finish
• Perfect for feeding a crowd or potlucks
• Versatile – add bacon, herbs, or different cheeses to customize
• Freezes well for convenient future meals

Ingredients

• 5 pounds russet or Yukon Gold potatoes, peeled and cut into chunks
• 1 cup whole milk or heavy cream (warmed)
• ½ cup sour cream
• 6 tablespoons unsalted butter
• 2 cups shredded sharp cheddar cheese (plus extra for topping)
• 1 teaspoon garlic powder (optional)
• Salt and freshly ground black pepper, to taste
• ½ cup green onions, sliced (for garnish)
• 1 cup breadcrumbs or fried onions (for crunchy topping, optional)

Equipment

• Large pot for boiling potatoes
• Potato masher or electric mixer
• Large mixing bowl
• 9×13-inch baking dish
• Oven

Step-by-Step Instructions

Step 1: Prepare the Potatoes

Place peeled and chopped potatoes in a large pot. Cover with cold salted water. Bring to a boil and cook until tender when pierced with a fork, about 15–20 minutes. Drain well.

Step 2: Mash the Potatoes

Return drained potatoes to the pot or a large bowl. Mash with a potato masher or beat with a mixer until mostly smooth. Avoid over-mixing to prevent gluey texture.

Step 3: Add Dairy and Flavorings

Stir in warmed milk or cream, sour cream, and butter. Add garlic powder if using, and season generously with salt and pepper. Mix gently to combine until creamy.

Step 4: Add Cheese

Fold in 2 cups shredded cheddar cheese, reserving some for topping.

Step 5: Transfer to Baking Dish

Spread the mashed potato mixture evenly in a greased 9×13-inch baking dish.

Step 6: Add Topping

Sprinkle remaining cheddar cheese evenly over the top. Add breadcrumbs or fried onions for an extra crunchy crust if desired.

Step 7: Bake

Bake uncovered at 350°F (175°C) for 25–30 minutes or until bubbly and golden on top.

Step 8: Garnish and Serve

Remove from oven and let rest for 5 minutes. Garnish with sliced green onions and serve warm.

Tips for the Best Mashed Potato Casserole

• Use starchy potatoes like russets for fluffier mash, or Yukon Golds for creamier texture.
• Warm dairy ingredients before adding to potatoes to prevent cooling and clumping.
• For extra richness, substitute sour cream with cream cheese or mascarpone.
• Don’t skimp on seasoning—potatoes need plenty of salt and pepper.
• Customize with add-ins like cooked bacon, chives, or sautéed mushrooms.
• Let casserole rest before serving to allow flavors to set.

Variations and Serving Suggestions

• Loaded Potato Casserole: Add cooked bacon bits, scallions, and a dollop of sour cream on top.
• Herbed Casserole: Stir in fresh thyme, rosemary, or parsley into mash.
• Spicy Twist: Add a pinch of cayenne or smoked paprika.
• Cheesy Crust: Top with a blend of mozzarella and Parmesan for an Italian flair.

Serve mashed potato casserole alongside roasted meats, grilled veggies, or steamed greens for a balanced meal. It’s also a favorite at holiday feasts where multiple sides shine.

FAQs

1. Can I make mashed potato casserole ahead?
   Yes, prepare the casserole and refrigerate covered for up to 24 hours then bake before serving.
2. How do I reheat leftovers?
   Reheat in a preheated 350°F oven, covered with foil to prevent drying, for about 20 minutes.
3. Can I freeze it?
   Yes, freeze in an airtight container before baking for up to 3 months. Thaw overnight before baking.
4. What if my potatoes are watery?
   Drain thoroughly after boiling. Adding extra butter and cheese helps balance moisture.
5. Do I have to use cheddar cheese only?
   No, try Monterey Jack, Gruyere, or a mix of cheeses for different flavors.
6. Can I add vegetables?
   Yes, stir steamed broccoli, peas, or caramelized onions into the mash.
7. Is there a dairy-free version?
   Use plant-based butter and milk alternatives like almond or oat milk.
8. How to get a crispy topping?
   Mix breadcrumbs with a little melted butter and sprinkle over the casserole before baking.

Conclusion

Mashed potato casserole is a crowd-pleasing classic that’s easy to customize and perfect for any occasion. Whether you keep it simple or add your own spin with extras, it’s a timeless dish everyone enjoys. This recipe’s creamy, cheesy texture and golden crust will make it a favorite in your recipe box.