Baked Mashed Potatoes With Sage butter

Baked mashed potatoes – creamy fluffy mashed potato with lots of cheese is baked into a casserole. While the potatoes are cheesy and creamy on the inside, the crust is beautifully caramelized and golden brown. Top it with brown butter and crispy sage, and you have a perfect side that will go with just about anything.

 creamy fluffy mashed potato with lots of cheese is baked into a casserole. Top it with brown butter and crispy sage

This Baked Mashed Potato with brown butter sage is much more than just mashed potato that’s baked. It is fluffy, loaded with chees, and has a golden crust. Sage brown butter adds nuttiness to the dish. An incredibly delicious potato side dish to serve with any meal.

There is no doubt that we love Garlic mashed potatoes and couldn’t have thought of serving any other side dish for the Holidays until I tried this Loaded Mashed Potato Bake. It is versatile and can be made ahead unlike mashed potatoes which need to be prepared just before serving as they tend to dry out. Not only that, this is a perfect recipe to upcycle any leftover mashed potatoes.

Everything is better with Cheese!

Well, I can’t deny the above statement. Anything with cheese tastes superior. Cheese adds richness and transforms this humble potato casserole into a decadent side dish. There is plenty of cheese in there. Shredded gruyere is stirred into the potatoes so that you can taste cheesy in every bite. Along with that, there is a surprise cheese layer in between, that melts and turns into gooey deliciousness. Though I love Gruyere in this recipe, you could use sharp cheddar, a blend of cheddar and parmesan, or gruyere and parmesan here.

 creamy fluffy mashed potato with lots of cheese is baked into a casserole. Top it with brown butter and crispy sage

Ingredients For Oven Baked Mashed Potatoes

The list of ingredients runs short here.

  • Yukon gold potatoes – Large Yukon gold potatoes.
  • Butter– Softened unsalted butter. Softened because it mixes with mashed potatoes well. You could use melted butter as well.
  • Milk – Warm full-fat milk. You can use heavy cream or half & half if you like the mashed potato rich.
  • Gruyere Cheese – I Love Gruyere cheese in my gratins and scalloped potatoes. But you can also use cheddar, a combination of cheese like cheddar and parmesan, or gruyere and parmesan, etc.
  • Garlic powder
  • Sage
  • Salt and pepper
Ingredients for baked mashed potatoes.

Steps to make Baked Potato Casserole

  1. Starchy potatoes like Russet or Yukon Gold potatoes work best in this recipe. Keeping the skin on or peeling it off is up to your personal preference. For smooth and creamy consistency take the peel off. Don’t cut the potatoes too small, as it they tend to absorb lots of water, and the mash will turn out runny.
  2. Once the potatoes are cooked, mash them while still hot. Stir in butter, milk, garlic powder, gruyere, salt and pepper. Fold everything just until everything is mixed. Hot potatoes absorb less water, so working fast and mixing everything while they are still hot gives you a fluffy, souffle-like texture.
  3. Spread half of the potatoes in a casserole dish. Sprinkle cheese and fill it up with the rest of the mashed potatoes. At this stage, you can bake or wrap it tightly with cling film and refrigerate for up to 2 days.
  4. Once it is baked, the crust is golden brown in colour. Spoon over the brown butter and crispy sage just before serving.
Step by step pohots showing hot to make baked mashed potato.

Storing leftover

This recipe is very forgiving. Leftovers can easily be stored up to 2-3 days in the refrigerator. Warm it in a microwave or back it in a preheated oven for 8-10 minutes. You can also freeze the dish once it is ensembled.

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 creamy fluffy mashed potato with lots of cheese is baked into a casserole. Top it with brown butter and crispy sage
Flavours of Kitchen Logo

Baked Mashed Potatoes With Brown butter Sage

Course Side Dish
Cuisine American
Prep Time 30 minutes
Cook Time 20 minutes
Creamy mashed potato is baked for a crispy crust and then topped with crispy sage cooked and brown butter.
Servings 6 servings


  • 6 large potatoes (approx 800 grams)
  • ½ cup full fat milk warm
  • 3 tablespoons Butter softened
  • 1 teaspoons garlic powder
  • ¾ teaspoons Salt
  • ¼ teaspoons Fresh cracked peppers
  • 1-1/4 cup Gruyere cheese

For Toppings

  • 2 tablespoons butter
  • 4-5 Sage leaves


  • Peel potatoes and rinse in cold water (cut potatoes in quaters if very large)
  • Preheat Oven 400 F / 200 C.
  • Cook Potatoes – Transfer them to a large stockpot filled with cold water. THe water needs to be 1 inch above the potatoes. Then turn the heat to high and cook until the water comes to a boil. Reduce heat to medium and continue cooking for 12-15 minutes until the potatoes are fork tender. Drain the potatoes immediately.
  • Mash Potatoes- While still hot, run potatoes through a potato ricer or transfer to the bowl of your stand mixer. Using the whisk attachment on low speed mash the potatoes. You can also use a potato masher instead.
  • To the mashed potatoes add softened butter, milk, garlic powder, half of the Gruyere cheese, salt, and pepper. Stir everything together using a spatula or wooden spoon until combined. The potatoes should be creamy and fluffy. Don't overmix or else the potatoes will turn gummy.
  • Spread half of the potatoes in the baking dish. Sprinkle remaining cheese. Layer with rest of the mashed potatoes. Smooth the surface with back of a spatula.
  • Bake for 20 minutes until the top is light golden brown in colour and lightly crispy. The cheese will start bubbling around the edges.
  • While potatoes are in the oven, melt butter in a pan. Cook on low heat until the butter is turning light golden yellow in colour and smells like caramel. Once it is just light golden yellow in colour, add sage leaves. Take it off the heat (butter and sage will continue cooking further in the remaining heat, so don't get tempted to cook longer).
  • Take potatoes out of the oven, spoon brown butter along with crispy sage leaves on top. Serve.


  1. Don’t cut potatoes too small as they absorb lot of water while cooking and will turn watery. 
  2. Once the potatoes are cooked, mash them while still hot. Butter, milk etc incorporates  well when potatoes are still hot or atleast warm. And results in fluffy cloud like mashed potatoes. 


Serving: 1serving | Calories: 289kcal | Carbohydrates: 40g | Protein: 7g | Fat: 12g | Saturated Fat: 7g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 3g | Trans Fat: 0.4g | Cholesterol: 34mg | Sodium: 424mg | Potassium: 932mg | Fiber: 3g | Sugar: 2g | Vitamin A: 379IU | Vitamin C: 12mg | Calcium: 112mg | Iron: 2mg
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