If you’re looking to elevate classic mashed potatoes into something worthy of a holiday spread—or simply want a comforting side that feels indulgent enough for any night of the week—this Sour Cream & Onion Mashed Potato Casserole is your answer. It brings together creamy, buttery mashed potatoes with the tang of sour cream, a hint of garlic, melted cheddar cheese, and fresh green onions, all baked into a golden, bubbly casserole.

This dish delivers everything you love about mashed potatoes with the added texture and depth that baking brings. As the casserole bakes, the top becomes slightly crisp and cheesy, while the inside stays irresistibly smooth and creamy. The flavor combination of sour cream and green onion mimics the nostalgic taste of sour cream & onion chips—only far more luscious and homemade.

Perfect for a cozy dinner, potluck, or special gathering, this casserole can be prepped ahead of time and baked when needed. It’s both family-friendly and impressive enough to serve guests. With optional toppings like crispy fried onions or a sprinkle of extra green onions for color and crunch, it’s the kind of side dish that might just steal the show.

Whether you’re pairing it with roast chicken, holiday ham, or enjoying it with a crisp salad, this casserole adds a hearty, flavorful touch to any meal. It’s comfort food with a twist—easy to prepare and guaranteed to become a repeat request.

Servings and Timing:

• Serves: 8–10
• Prep Time: 20 minutes
• Bake Time: 30 minutes
• Total Time: 50 minutes

Ingredients:

• 3 lbs russet or Yukon gold potatoes, peeled and chopped
• 1 cup sour cream
• 4 tablespoons butter
• ½ cup milk (add more for creamier consistency)
• 1½ cups shredded cheddar cheese, divided
• 4 green onions, thinly sliced
• 1 teaspoon garlic powder
• Salt and pepper to taste

Optional Topping:

• Crushed fried onions or extra green onions for garnish

Instructions:

1. Bring a large pot of salted water to a boil. Add the chopped potatoes and cook for 15–20 minutes or until fork-tender. Drain well.
2. Return the potatoes to the pot and mash with butter, milk, sour cream, garlic powder, salt, and pepper until smooth and fluffy. Adjust the milk for desired creaminess.
3. Stir in 1 cup of the shredded cheddar cheese and most of the sliced green onions, reserving a few for topping if desired.
4. Spoon the mashed potato mixture into a greased 9×13-inch baking dish, spreading evenly.
5. Sprinkle the remaining ½ cup of cheese over the top.
6. Bake in a preheated 375°F (190°C) oven for 25–30 minutes, or until the casserole is hot and the cheese is melted and bubbly.
7. Garnish with additional green onions or a layer of crispy fried onions before serving, if desired.

Variations:

• Loaded twist: Add chopped cooked bacon or sautéed mushrooms for extra depth.
• Cheese swap: Use Monterey Jack or gouda for a different cheesy flavor.
• Make it spicy: Stir in a pinch of cayenne or diced jalapeños for a kick.
• Dairy-free option: Use plant-based milk, vegan butter, and dairy-free cheese and sour cream.

Tips:

• Yukon gold potatoes offer a naturally buttery texture that’s great for mashing.
• For extra smooth potatoes, use a ricer or hand mixer to blend the mash before baking.
• This dish can be assembled a day in advance and refrigerated—just increase the bake time by 5–10 minutes if baking from cold.
• Leftovers reheat beautifully in the oven or microwave and make a great next-day side.

This Sour Cream & Onion Mashed Potato Casserole brings a cozy, cheesy spin to a beloved classic, making it a standout side for everything from casual dinners to celebratory feasts. It’s comfort food at its finest—warm, satisfying, and guaranteed to please.