Mashed Potato Casserole

Creamy, cheesy, and deeply comforting, this Mashed Potato Casserole is the kind of dish that solves dinner in the most satisfying way possible. If you’re looking for a crowd-pleasing casserole that feels both cozy and indulgent, this recipe delivers from the very first bite. Fluffy mashed potatoes form the base, topped with savory beef and a generous layer of melted cheese, all baked until golden and bubbly. Whether you need a make-ahead side for gatherings or a hearty family meal, this casserole is designed to be simple, reliable, and irresistibly delicious.

Table of Contents

Table of Contents

Why You’ll Love This Recipe

• Comfort Food at Its Best – Creamy mashed potatoes, savory beef, and melted cheese hit all the right notes.
• Make-Ahead Friendly – Perfect for holidays or busy days when you want to prep in advance.
• Simple Ingredients – Everything comes from familiar, easy-to-find pantry staples.
• Crowd-Pleaser – Ideal for family dinners, potlucks, or special occasions.
• Extra Creamy Texture – A careful mashing method keeps the potatoes fluffy, never gluey.

What sets this version apart is the balance: rich but not heavy, cheesy without overpowering the potatoes, and structured enough to slice while still being luxuriously soft.

Ingredients Needed

For the Mashed Potato Base

• 1.75 kg / 3.5 lb potatoes (Russet, Maris Piper, King Edwards, or similar starchy potatoes) – peeled and cut into chunks
• 1 tbsp cooking or kosher salt – for boiling the potatoes
• 2/3 cup whole milk – warmed slightly for smoother mashing
• 2/3 cup extra milk – only if making ahead, to keep the potatoes creamy
• 75 g (5 tbsp) unsalted butter – cut into small cubes
• 1/2 cup full-fat sour cream or yogurt – for richness and tang
• 1 tsp cooking or kosher salt – or to taste

For the Topping

How to Make Mashed Potato Casserole

Cook the Ground Beef

1. Place the ground beef in a cold non-stick pan without oil. Starting cold allows the fat to slowly render, adding flavor.
2. Set the pan over medium heat. As the fat melts, stir gently to break up the meat.
3. Increase the heat to medium-high and cook for about 3 minutes, stirring, until the beef turns golden and slightly crisp.
4. Transfer to paper towels to drain excess fat. Set aside.

Prepare and Mash the Potatoes

1. Peel the potatoes and cut them into 3 cm / 1-inch chunks for even cooking.
2. Place them in a large pot and cover with water so it rises about 10 cm / 4 inches above the potatoes. Add 1 tablespoon salt.
3. Bring to a boil, then reduce to a rapid simmer. Cook for 15 minutes, or until the potatoes are extremely tender and fall apart when pierced with a fork.
4. Drain thoroughly and return the potatoes to the hot pot. Let them sit for 1 minute, shaking the pot occasionally—this helps excess moisture evaporate.
5. Add milk (and extra milk if making ahead), butter, sour cream, and 1 teaspoon salt.
6. Mash gently until smooth and fluffy. Tip: Avoid blenders or food processors—they overwork the starch and make potatoes gluey.

Make-Ahead Option (If Needed)

• Let the mashed potatoes cool completely at room temperature.
• Cover tightly and refrigerate.
• Remove from the fridge 2 hours before baking to take the chill off.

Assemble and Bake

1. Preheat the oven to 200°C / 400°F (180°C fan).
2. Spread the mashed potatoes evenly into a 2-liter / 2-quart baking dish, smoothing the top.
3. Sprinkle the cheeses evenly over the surface, followed by the cooked ground beef.
4. Cover loosely with foil and bake for 20 minutes (fresh) or 35 minutes (make-ahead).
5. Remove the foil and bake for another 10 minutes, until the cheese is melted, bubbly, and lightly golden.
6. Finish with sliced green onions and serve hot.

Serving and Storage Tips

• Serving: Serve straight from the baking dish with a simple green salad or roasted vegetables for balance.
• Storing: Store leftovers in an airtight container in the refrigerator for up to 3 days.
• Reheating: Reheat covered in the oven at 180°C / 350°F, or microwave individual portions until heated through.

Helpful Notes

• Use starchy potatoes only—waxy potatoes won’t mash as smoothly.
• Shred cheese yourself for better melting; pre-shredded cheese can be grainy.
• You can swap ground beef for turkey or skip it entirely for a vegetarian version.
• For extra richness, add a small knob of butter on top before baking.

Conclusion

This Mashed Potato Casserole is proof that simple ingredients can create something truly special. With its ultra-creamy base, savory beef, and golden cheese topping, it’s the kind of dish that disappears fast at the table. It’s easy enough for weeknights, yet impressive enough for holidays and gatherings. If you tried this recipe, I’d love to hear from you—leave a comment and a ⭐ star rating below. Don’t forget to share it on Pinterest or Facebook! What twist did you add to make it your own?

Frequently Asked Questions (FAQ)

Can I make this casserole ahead of time?

Yes. Prepare the mashed potatoes with the extra milk, assemble, refrigerate, and bake when needed.

Can I freeze mashed potato casserole?

Yes, but the texture may change slightly. Freeze tightly wrapped for up to 1 month and thaw overnight before reheating.

How do I keep mashed potatoes from being gluey?

Avoid overmixing and never use a blender or food processor. Mash gently by hand.

Can I make this recipe gluten-free?

Absolutely. All the ingredients are naturally gluten-free—just double-check your cheese labels.

How thick should the mashed potatoes be?

They should be creamy and soft but able to hold their shape when spread, not runny.