Make-Ahead Mashed Potatoes (Mashed Potato Casserole)

Sharing my personal chef secrets for how I do mashed potatoes for clients so they reheat beautifully and stay light and fluffy. Make-Ahead Mashed Potatoes (Mashed Potato Casserole) are smooth, creamy, slightly cheesy, garlicky, a little bit tangy and a whole lot delicious. Best of all, they can be made two days ahead and baked when you need them or two hours ahead and kept hot in your slow cooker!

Why This Recipe Is a Keeper:

Sometimes referred to as a Mashed Potato Casserole, these Make-Ahead Mashed Potatoes are everything! Smooth, creamy, slightly cheesy, garlicky, a little bit tangy and a whole lot delicious! A potato ricer takes care of any lumps and minimal stirring/processing keeps them light, fluffy and far from gummy.

This Make-Ahead Mashed Potatoes recipe is based on some food science put forth by Cook’s Illustrated (a membership site so I can’t link) and food scientist Shirley Corriher where butter goes into the potatoes before any other dairy is added. According to Cook’s Illustrated, adding melted butter first–before any liquid–coats the starch in the potatoes with fat so it can’t absorb liquid which is what leads to gluey mashed potatoes. Shirley Corriher says the fat from the butter gets absorbed into the cells of the potatoes first then the milk (or the rest of the dairy) loosens and flavors the potatoes. Here’s all the information at Food52 which I can link to: A Genius Trick for More Buttery-Tasting Mashed Potatoes.

Reheating the Make-Ahead Mashed Potatoes (Mashed Potato Casserole) in the oven makes them souffle-like and produces light, golden, crispy edges everyone will fight over! You can also keep them hot in your slow cooker for up to two hours.

I’ve made them this way hundreds of times for personal chef clients over 20 years and for my family with not a single complaint. My clients even freeze them and they still reheat beautifully.

Perfect on the side with my Red Wine Braised Beef Short Ribs, Mississippi-Style Boneless Short Ribs and of course, Roast Turkey Breast with Traditional Stuffing!

Let’s make ’em!

Recipe Ingredients:

Ingredient Notes:

• Russet Potatoes: Russet potatoes are my favorite potatoes for mashed potatoes because of their high starch content. Yukon Gold or red will work but their “waxy” nature can get gummy a little too quickly.
• Garlic: Fresh garlic is best but I have used a little garlic powder added to the melted butter in a pinch.
• Butter: I always use unsalted butter in cooking because I can control the amount of salt.
• Sour Cream: I use full-fat sour cream but light sour cream does work.
• Cream Cheese: Here too, full-fat but light cream cheese (Neufchatel) does work. Let soften before using in the mashed potatoes.
• Half-and-Half: I like half-and-half the best for mashed potatoes (half cream, half whole milk) and I always have it on hand because it’s what I put in my coffee.

Step-By-Step Instructions:

• Gather and measure out all the ingredients.
• Spray a 13 x 9-inch baking dish or two smaller dishes with cooking spray.
• So that the potatoes don’t start discoloring before you get them all peeled, fill a pot with an estimated amount of cold water you think will cover the potatoes. You can add or remove water later but you want the water to just cover the potatoes.
• Then, peel the potatoes, rinse to ensure they’re clean and cut into even chunks and place in the water. (I usually cut them into 1 to 1 ½-inch chunks.)
• Add 8-10 peeled cloves of garlic in the water along with a generous amount of salt–approximately 1 tablespoon.

• Place the pot with the potatoes on the stove, turn the heat to HIGH, then place a stick of butter in a stainless steel bowl and set it over the potatoes.
• Keep an eye on the butter and remove it from the top of the pot when it is melted or almost melted. Do not let the pot boil over. Add 1 teaspoon salt then set the butter aside to cool. You can also do this in a small saucepan to pour over the riced potatoes.

• Cook the potatoes until they can be easily pierced with a paring knife.
• Drain well, then place back on the hot burner for just a couple minutes so any residual water steams away. You’ll notice the edges of the potatoes turning a little whiter.

• Then, working quickly so the potatoes don’t cool too much, start pushing the potatoes and garlic while they’re still hot and steaming into the melted butter. (I find disposable gloves help tremendously in handling the hot potatoes.)

• Keep going until you have all the potatoes “riced.”

• You still have to work quickly so the potatoes don’t cool and you end up with firm “riced” potatoes.
• Quickly stir the potatoes to incorporate and distribute the butter.

• Push the potatoes off to one side of the bowl.
• In the other half, place the sour cream, cream cheese and half-and-half.
• Puree the sour cream, cream cheese and half-and-half with an immersion blender avoiding the potatoes. Do not puree the potatoes with the immersion blender. A hand mixer also works to blend the sour cream, cream cheese and half-and-half but it takes longer. (You can also do this in a separate bowl then add it to the potatoes. However, this is how I do it at a client’s home to reduce the number of bowls and pots I use.)

• Then stir the potatoes into the sour cream, cream cheese and half-and-half blend.
• You may think you’re going to have potato soup, but it all comes together into a lovely creamy blend.

• Transfer the potatoes to the prepared baking dish(es). Cool and refrigerate.
• When ready to bake, preheat your oven to 375 degrees and bake until the potatoes are puffy, the top is lightly golden and the potatoes are thoroughly heated through.

Beautiful, poofy, fluffy Make-Ahead Mashed Potatoes!

Chef Tips and Tricks:

• When boiling potatoes, you always want to start with cold water. If you start with hot water or boil the water first then add the potatoes, the potatoes cook unevenly.
• Over the years of my personal chef career, I’ve had to learn how to reduce the amount of pots, pans and bowls I use and reduce steps. Placing the bowl with the butter over the pot of potatoes both melts the butter and helps the pot of potatoes boil a bit faster. However, as stated above, keep an eye on the butter so it just melts and so the potatoes don’t boil over.

Frequently Asked Questions:

Variations:

There are so many things you can do with this recipe! You can add:

• Roasted garlic
• Horseradish
• Mustard
• Different types of cheese such as Cheddar, Gruyere, blue cheese or Parmesan
• Chipotle chiles or Hatch green chiles
• Bacon
• Rosemary or other herbs such as chives
• Pesto
• Artichokes
• Caramelized onions
• Pretty much anything!

More potato recipes you can make ahead!

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