This make-ahead loaded mashed potato casserole has everything you want in a potato dish. Creamy layers covered with toppings make a delicious and irresistible side dish that will make everyone ask for seconds. Not to mention, it makes a wonderful side dish for Thanksgiving, Christmas, or any night in between.
Can’t get enough of mashed potatoes? Also, try my Rosemary Mashed Potatoes recipe.
Why Should You Try This Recipe?
Talk about a double-layered treat! This casserole with mashed potatoes has become a favorite side dish at dinner parties and holiday celebrations. I know your friends and family will go crazy for this one. Here’s why:
- It’s a two-for-one potato recipe! No longer do you have to choose between sweet or savory potatoes – this great recipe is the perfect way to have the best of both worlds!
- Easy to make ahead of the week you are going to serve. Simply make the recipe to completion, then pop it in the oven the day of serving to heat it back up!
- Simple enough to make as part of a celebratory weeknight dinner and festive enough to include as part of your holiday meal (i.e., Easter dinner, Thanksgiving meal or Christmas spread)
- Inspired by my Easy Mashed Sweet Potatoes and Sweet Potato Casserole recipes, this loaded mashed potato casserole is visually impressive too.
Ingredients
The ingredient list for this mashed potato recipe for dinner is super simple and not unlike what you would have put on your grocery list for traditional mashed potatoes.
Gather together sweet potatoes, Yukon gold potatoes, Kosher salt, milk, cream, butter, and black pepper. The totally optional, but totally craveable, crispy leek topping includes all-purpose flour, leeks, and avocado oil.
- Sweet potatoes: My favorite sweet potato variety is Garnet, which I find to be super bright orange and extra starchy. Jewel is another great option, as well as Beauregard, the most common type of sweet potato sold in grocery stores.
- Yukon gold potatoes: These provide an extra creamy texture and rich flavor. Russet or red potatoes (like it is in this red-skinned mashed potatoes recipe)
- Toppings to make it “loaded”: I used lightly fried leeks, crispy turkey bacon, and fresh herbs as a topping but they are optional and can be omitted if you like.
How to Make It?
Once I realized I could combine sweet potatoes and white potatoes into a baked mashed potato casserole masterpiece, my life was completely transformed. The crispy leeks at the very end add that extra bit of finesse (especially if you are serving it as a holiday side dish) and savory bite but they are optional.
- Boil potatoes: Place sweet potatoes and Yukon gold potatoes in two separate saucepans (I used my 3-quart saucepan for cooking them). Cover each pot of potatoes with enough water to cover them. Season water generously with salt. Bring them to a boil and let them cook until they are fork-tender. Drain. Return potatoes to respective pans. Here is a helpful tutorial on How To Boil Potatoes, if you are new to cooking potatoes.
- Mash potatoes: Pre heat oven to 400 °F. Whisk together the ¾ cup milk, ¾ cup heavy cream, and 4 oz. (1 stick) melted and cooled butter in a mixing bowl. Divide the mixture in between the saucepans. Using a potato masher or hand mixer, mash potatoes until smooth. Give it a taste and season with salt and pepper.
- Layer potato casserole: Spread mashed sweet potatoes in an oval-shaped (or 9 x 11 inch rectangular) casserole dish. Using the back of a spoon or a spatula, smooth out the top into one even layer. Top with the mashed Yukon gold potatoes and spread it evenly to the edges, creating delicate divots and crevices.
- Bake: Bake until golden, 20-25 minutes.
- Fry leeks: Meanwhile, mix together the flour, leeks and a pinch of salt. Toss to coat. Heat the avocado oil in a medium saucepan over medium-high heat for 2 minutes. Add leeks into the oil and fry, turning occasionally, until crisp and golden around the edges. Transfer the crispy leeks onto a plate lined with a paper towel. Season the crispy leeks with additional salt and pepper.
- Finish and serve: Sprinkle the leeks and bacon crumbles (if using) over the potato casserole. Serve immediately.
Variations
Now comes the fun part! This whipped potato casserole can be customized to become the best loaded mashed potatoes recipe in the world. You could try:
- Bacon: Use my method for oven-baked turkey bacon (or air-fried turkey bacon) or bake a batch of regular bacon to crumble into bacon bits on top. I used 6 slices of bacon but if you want to use more I don’t think that anyone will complain.
- Garlic: Toss a few cloves of peeled garlic cloves into the water with the cubed potatoes. Boil and mash right into the creamy potatoes when mixing. If not, you can add in a few teaspoons of garlic powder into the potato mixture.
- Cheese: The recipe below is made without cheese, but you can always add some in. Parmesan cheese, shredded Cheddar cheese, or Monterey Jack cheese would all be delicious. Sprinkle about ½ cup shredded cheese before baking in the oven for a cheesy mash bake.
- Sour Cream: Add in ¼ cup sour cream with the milk mixture for an extra tangy bite.
- Cream Cheese: Sub out ½ cup heavy cream for 4 ounces (½ block) full fat cream cheese.
- Italian Parsley and/or Chives: Sprinkle 2 tablespoons of fresh parsley and chives on top when you add the crispy leeks. You can also add chopped green onions.
- Low Fat milk: Replace the whole milk with 2% or skim milk, if desired.
- Dairy-free option: If you are after a dairy-free potato as a side, then check out this Dairy-Free Scalloped Potatoes recipe.
How to Serve?
Since this is a mashed potatoes casserole for a crowd, I serve it as a side dish at dinner parties (check out some recommendations below!), as well as part of my holiday spread during Thanksgiving and Christmas.
As soon as your guests stick a spoonful into this double layered potato casserole, everyone goes wild. You can also drizzle it with my homemade beef gravy if you want to take it up a notch.
What to Make with Mashed Potatoes as a Side?
A few of my favorite main dishes with mashed potato casserole include:
How to Make Ahead and Storage Instructions
This is an easy loaded mash that can be assembled ahead of time, then stored in the fridge or freezer until the day you are ready to serve. Here are my tips for each of the following:
- Mashed Potatoes: Boil, mash and assemble the two layers, then wrap the entire casserole dish in plastic wrap, then in foil. Bring to room temperature and store in the fridge for up to 3 days or in the freezer for up to 1 month. Thaw overnight in the fridge, if frozen. Reheat in a 350 degree F oven until the center is warmed through.
- Crispy Leeks: Prepare on the day you are going to serve while the casserole is reheating in the oven.
Expert Tips
Here are some of my best tips to get this recipe right every time:
- Don’t overmix the potatoes, or they will have a gummy texture.
- Bring all ingredients to room temperature. Room temperature milk, cream, and slightly warm melted butter blend better with warm potatoes.
- Create deep pockets of divots and peaks on the top layer of the potato casserole just before baking. This ensures a golden crust with deep, dark, caramelized bits.
- Add toppings after baking. No matter if you stick with the crispy leeks, or go fully loaded with bacon and chives, add after baking to keep the integrity of the toppings. The exception to this rule is cheese – add that while baking for a delectable cheesy finish.
- Rinse leeks after slicing. The inside layers of leeks are full of excess dirt and soil. I always trim and slice my leeks first, then place in a bowl of cool water and slosh them around a few times to allow the grit to fall to the bottom. Remove with a slotted spoon and pat dry with paper towels before frying.
- Salt your cooking liquid: The easiest way to make your potatoes flavorful is to generously salt your cooking liquid. This way, it will be properly salted as it boils and as a result, will not require too much salt later.
- If you have some leftover mashed sweet and savory potatoes, you can skip making them from scratch and bake them as suggested in the recipe.
FAQs
My favorite sweet potato is Garnet, with Jewel and Beauregard varieties being the next best thing. My favorite white potato is Yukon gold, with russet potatoes or red potatoes as good options, too.
Yes! Follow the recipe up until layering the potatoes in the casserole dish, then cover tightly with plastic wrap. Keep in the fridge for up to 4 days. Reheat in a 350 degree F oven until warmed through. Make the crispy leeks the day you are going to serve and enjoy.
Yes! Although I find the taste and texture to be best when made the day or week of, mashed potatoes can be frozen to really get ahead as the fat from the cream and butter helps to protect the starchy potato. Bring it to room temperature, wrap the entire casserole dish in plastic wrap, then in foil, and freeze for up to 1 month. Thaw overnight in the refrigerator before reheating.
Other Potato Recipes You Might Also Like:
It is no secret that potatoes make the best side dishes. Below are a few other recipes that you might also like:
- Roasted Sweet Potatoes and Brussels Sprouts
- Sweet Potato Noodles Recipe
- Potato Salad Recipe
- Vegan Sweet Potato Soup Recipe
- No Mayo Potato Salad
- Muffin Tin Potatoes
If you try this Loaded Mashed Potato Casserole recipe or any other recipe on Foolproof Living, please take a minute to rate the recipe and leave a comment below. It helps others who are thinking of making the recipe. And if you took some pictures, be sure to share them on Instagram using #foolproofeats so I can share them on my stories.
Mashed Potato Casserole Recipe
Ingredients
For the mashed potatoes:
- 2 pounds, 3-4 medium sweet potatoes, peeled and cut into small cubes
- 2 pounds, 4-5 medium Yukon gold potatoes, peeled and cut into small cubes
- Kosher salt
For the milk & cream mixture:
- ¾ cup whole milk
- ¾ cup heavy cream
- 1 stick butter, melted and cooled - 4oz.
- Freshly cracked black pepper
For the toppings (Optional)
- 2 tablespoons all purpose flour
- 1 leek, white and pale green parts only, cut into ¼-inch rings, rinsed well and patted dry
- 2-3 tablespoons avocado oil
- 6 slices bacon, or turkey bacon Cooked - (Omit for vegetarian version)
Instructions
- Boil potatoes: Place sweet potatoes and Yukon gold potatoes in two separate saucepans. Cover each pot of potatoes by 1-inch of water. Salt them generously. Bring them to a boil and let them cook until they are fork tender. Drain. Return potatoes to respective pans.
- Mash potatoes: Preheat the oven to 425 °F. Whisk together the milk, heavy cream, and butter in a mixing bowl. Divide the mixture in between the saucepans. Using a potato masher or hand blender, mash potatoes until smooth. Season with salt and pepper.
- Lightly spray a casserole dish with cooking spray. I used an oval-shaped (or 9 x 11 inch rectangular) casserole dish.
- Layer potatoes: Spread mashed sweet potatoes in the prepared casserole dish. Using the back of a spoon or a spatula, smooth out the top into one even layer. Top with the mashed Yukon gold potatoes and spread it evenly to the edges, creating delicate divots and crevices.
- Bake: Bake until golden, 20-25 minutes.
- Fry leeks: Meanwhile, mix together the flour, leeks and a pinch of salt. Toss to coat. Heat the avocado oil in a medium saucepan over medium-high heat for 2 minutes. Add leeks into the oil and fry, turning occasionally, until crisp and golden around the edges. Transfer the crispy leeks onto a plate lined with a paper towel.
- Finish and serve: Season the crispy leeks with additional salt and pepper. Sprinkle them over the potato casserole. Serve immediately.
Notes
- Don’t overmix the potatoes, or they will have a gummy texture.
- Bring all ingredients to room temperature. Room temperature milk, cream, and slightly warm melted butter blend better with the warm potatoes.
- Create deep pockets of divots and peaks on the top layer of the potato casserole just before baking. This ensures a golden crust, with deep, dark, caramelized bits.
- Add toppings after baking. No matter if you stick with the crispy leeks, or go fully loaded with bacon and chives, add after baking to keep the integrity of the toppings. The exception to this rule is cheese - add that while baking for a delectable cheesy finish.
- To make ahead - Boil, mash and assemble the two layers, then wrap the entire casserole dish in plastic wrap, then in foil. Bring to room temperature and store in the fridge for up to 3 days or in the freezer for up to 1 month. Thaw overnight in the fridge, if frozen. Reheat in a 350 degree F oven until the center is warmed through.Crispy Leeks: Prepare on the day you are going to serve while the casserole is reheating in the oven.
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
The recipe for this Double Layered Mashed Potato Baked Casserole is adapted (with a few changes) from the cookbook, Martha Stewart’s Vegetables.
This looks and sounds absolutely delicious! My mom always does scalloped potatoes with crispy shallots on top – that’s a winner too! Crispy is always a winner 😉
Ooooh I know. I love scalloped potatoes as well. Crispy shallots sound great as well.
Thanks my friend. I hope you are enjoying your Thanksgiving.
Oh myyy!! I love the double layer, and I say gimme all the fried leeks – why not!? Occassionally I fry too… and it’s all good, especially when leeks are involved! I didn’t know Martha had a new book out.. and I love that it has loads of veggie options (!!). I’ll check it out! Nice work on the GIF! Have a wonderful, restful holiday my dear! xo
Ha ha.. I love fried food so much. And crispy leeks has a special place in my heart. 🙂
Thank you so much for all your kindness and support my friend. You, too have a great rest of the year.
Cheers!