This baked cheesy mashed potatoes, also known as mashed potato casserole, is so delicious and packed full of flavor. It is rich, fluffy, creamy and cheesy, making it the perfect side dish for any meal. Make this cheesy baked potato for Easter, Christmas, Thanksgiving, special occasions, or part of your Sunday roast dinner.
Love mashed potatoes with cheese? Try my ricotta mashed potato, Boursin mashed potatoes, and Boursin mashed cauliflower recipe.

This cheesy mashed potato casserole will be the talk of your table at family dinners, potlucks, or holiday gatherings. It is amazingly good and very easy to make. Like every other typical mashed potato recipe, it starts by boiling the best spuds and adding butter, milk, and seasoning. This recipe stands out by infusing fresh thyme and garlic into the boiling process for exceptional flavor.
After the potatoes are boiled, they are mashed with a potato ricer for the best fluffy and creamy texture. Then comes the cheesy goodness of sharp cheddar cheese, gruyere, and mozzarella cheese. The mixture is then perfectly seasoned and then placed in a baking dish, and topped with more cheese before being baked to perfection. This recipe is for you if you love comfort food.
You may be wondering why I didn't use sour cream or parmesan cheese in this recipe. It doesn't need them, and I wanted to keep it simple without compromising flavor and texture. However, feel free to add any other cheeses or ingredients you like to make it your own. Let's get cooking!
Related recipe: air fryer cauliflower cheese
What you will need
Potatoes
Sharp cheddar cheese
Mozzarella cheese
Gruyere cheese
Fresh garlic: substitute with roasted garlic
Fresh thyme
Milk
Unsalted butter
Fresh parsley
How to make baked cheesy mashed potatoes
Peel the potatoes and cut them into large chunks similar in size so they cook evenly. Place the chopped potatoes in a large pot over high heat and cover with water about 2 inches above them. Add salt, fresh thyme, and garlic and stir briefly to combine.
Preheat the oven to 400F /200C.
Reduce the heat to medium-high and boil the potatoes until fork tender, about 12-15 minutes. Drain the potatoes completely (remove the thyme stem) and return them to the pot. Let them cool while you heat the milk and butter.
In the meantime, Heat the milk and butter in a saucepan until the butter melts. Remove the pan from the heat and set aside.
Using a potato ricer, handheld masher or electric potato masher, mash the potatoes until smooth and creamy.
Slowly pour in the milk and butter mixture, stirring continuously, until well combined. Next, add chopped parsley and season with salt and pepper to taste.
Add in the shredded mozzarella, gruyere, and cheddar cheese and gently fold it into the mashed potatoes.
Transfer the mashed potato mixture to a casserole dish and spread the top evenly. Lastly, top with more shredded cheese.
Bake in the oven until the cheese is melted, bubbly and golden brown, about 20-25 minutes. For a more golden brown crust on top, switch to broil for the last few minutes of baking.
Remove the baking dish from the oven and leave to cool slightly.
Serve hot as a side dish with your favorite protein, vegetables and gravy for a complete meal.
Watch how to make it
Variation and tips
- Swap whole milk for heavy cream for extra richness
- Add sour cream, ricotta cheese, or cream cheese for that extra creaminess
- Top the casserole with grated parmigiano reggiano or panko breadcrumbs for a crispy topping
- Add in chopped cooked crispy bacon, green onions, or chives for added flavor and texture
- Experiment with different types of cheese, such as blue cheese or gouda, to create unique variations of this recipe.
- If you don't have fresh thyme, you can use dried thyme instead - just reduce the amount to 1 teaspoon.
- Swap butter for a plant-based one, and use dairy-free cheese and milk alternatives for a vegan option.
- Instead of boiling the potatoes with water, use low-sodium chicken or vegetable stock for additional flavor.
How to serve
Serve this baked cheesy mashed potato casserole alongside your favorite main dishes and vegetables like roasted chicken, oven steak, baked pork chops.
Baked Cheesy Mashed Potatoes
Ingredients
- 1.2 lb potatoes Maris Piper, King Edward, Russets and the likes.
- 6 Tablespoons unsalted butter
- 1 cup sharp cheddar cheese
- ½ cup mozzarella cheese
- ½ cup gruyere cheese
- 3 garlic cloves
- 3 springs fresh thyme
- 1½ cups Milk You can use up to 2 cups
- Salt and black pepper to taste
- 2 Tablespoons parsley finely chopped
Instructions
- Peel the potatoes and cut them into large chunks similar in size so they cook evenly. Place the chopped potatoes in a large pot over high heat and cover with water about 2 inches above them. Add salt, fresh thyme, and garlic and stir briefly to combine.1.2 lb potatoes, 3 garlic cloves, 3 springs fresh thyme, Salt and black pepper to taste
- Preheat the oven to 400F /200C.
- Reduce the heat to medium-high and boil the potatoes until fork tender, about 12-15 minutes. Drain the potatoes completely (remove the thyme stem) and return them to the pot. Let them cool while you heat the milk and butter.
- In the meantime, Heat the milk and butter in a saucepan until the butter melts. Remove the pan from the heat and set aside.6 Tablespoons unsalted butter, 1½ cups Milk
- Using a potato ricer, handheld masher or electric potato masher, mash the potatoes until smooth and creamy.
- Slowly pour in the milk and butter mixture, stirring continuously, until well combined. Next, add chopped parsley and season with salt and pepper to taste.
- Add in the shredded mozzarella, gruyere, and cheddar cheese (reserving some to top the casserole later) and gently fold it into the mashed potatoes.1 cup sharp cheddar cheese, ½ cup mozzarella cheese, ½ cup gruyere cheese
- Transfer the mashed potato mixture to a casserole dish and spread the top evenly. Lastly, top with the more shredded cheese.
- Bake uncovered in the oven until the cheese is melted, bubbly and golden brown, about 20-25 minutes. For a more golden brown crust on top, switch to broil for the last few minutes of baking.
- Remove the baking dish from the oven and leave to cool slightly.
- Serve hot as a side dish with your favorite protein, vegetables and gravy for a complete meal.
Notes
- Swap whole milk for heavy cream for extra richness Add sour cream, ricotta cheese, or cream cheese for that extra creaminess.
- Top the casserole with grated parmigiano reggiano or panko breadcrumbs for a crispy topping.
- Add in chopped, cooked, crispy bacon, green onions, or chives for added flavor and texture.
- Experiment with different types of cheese, such as blue cheese or gouda, to create unique variations of this recipe.
- If you don't have fresh thyme, you can use dried thyme instead - just reduce the amount to 1 teaspoon.
- Swap butter for a plant-based one, and use dairy-free cheese and milk alternatives for a vegan option.
- Instead of boiling the potatoes with water, use low-sodium chicken or vegetable stock for additional flavor.
Nutrition
Nutritional data: Please note that the nutrition label provided is an estimate based on an online nutrition calculator. It will vary based on the specific ingredients and brands you use. Under no circumstances will thedinnerbite.com be responsible for any loss or damage resulting for your reliance on nutritional information.
And there you have it, a simple and delicious cheesy baked casserole recipe you can make at home. As always, if you made this recipe, I would love to hear from you! Kindly rate the recipe 5 star and leave me feedback in the comment section below. Tag me @thedinnerbite on Instagram and save it away to your Pinterest. Please subscribe to the blog if you haven’t for free new recipes in your inbox.
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