Simple Oat Milk Mashed Potatoes

I grew up thinking mashed potatoes absolutely had to have butter and cream to taste good. That’s what my mom used, and honestly, they were delicious. But after my family started keeping oat milk in the fridge, I decided to try it in my mashed potatoes one night when I ran out of cream.

Turns out, you don’t need dairy at all. Oat milk makes mashed potatoes just as creamy and smooth as the traditional way. The trick is using full-fat oat milk at room temperature—cold oat milk straight from the fridge can make your potatoes gluey. Add some garlic and green onions, and you’ve got a side dish that tastes rich without any butter or cream involved.

What Kind of Potatoes Should I Use?

For the creamiest mashed potatoes, you’ll want to reach for Yukon Gold potatoes – they have a naturally buttery flavor and smooth texture that works perfectly in this recipe. Russet potatoes are another solid choice if that’s what you have on hand, though they tend to be a bit more starchy and can get gummy if you overmix them. Red potatoes will give you a slightly chunkier, more rustic mash since they hold their shape better, which some people actually prefer. Whatever type you choose, just make sure to cut them into evenly sized cubes so they cook at the same rate and you don’t end up with some pieces that are mushy while others are still firm.

Options for Substitutions

This recipe is pretty straightforward, but here are some swaps you can make if needed:

• Oat milk: You can use any plant-based milk you have on hand – almond, soy, or cashew milk all work well. Just make sure to use the full-fat or unsweetened versions for the best creamy texture. Regular dairy milk or half-and-half also work if you’re not keeping it dairy-free.
• Potatoes: Russet potatoes are ideal for fluffy mashed potatoes, but Yukon golds give you a creamier, buttery result. You can also mix both types. Red potatoes work too, though they’ll be a bit denser and less fluffy.
• Garlic cloves: If you’re not a fan of whole garlic cloves, you can use 1 to 2 teaspoons of garlic powder instead. Add it when you’re mashing the potatoes.
• Green onions: Chives make a great substitute and give a similar mild onion flavor. Regular chopped onions work too, but they’re a bit stronger, so use less.
• Lemon juice or vinegar: Either one works to add a subtle tang. If you don’t have either, you can skip it – the mashed potatoes will still taste great, just without that little brightness.

Watch Out for These Mistakes While Cooking

The biggest mistake when making mashed potatoes is draining them too quickly after boiling, which doesn’t give excess moisture time to evaporate – let the potatoes sit in the colander for a minute or two so they steam dry and won’t turn watery when you add the oat milk.

Another common error is adding cold oat milk straight from the fridge, which can make your potatoes gummy and cool them down too fast, so warm it up in the microwave for 30 seconds first.

Overmixing is the enemy of fluffy mashed potatoes since it activates the starch and creates a gluey texture – use a potato masher or ricer and stop as soon as you reach your desired consistency, even if a few small lumps remain.

Finally, don’t skip seasoning throughout the process by adding salt to the cooking water, which helps the potatoes absorb flavor from the inside out rather than just tasting it on the surface.

What to Serve With Oat Milk Mashed Potatoes?

These creamy mashed potatoes are the perfect side dish for just about any protein you’re serving for dinner. They pair beautifully with roasted chicken, pan-seared pork chops, or a juicy steak – basically anything that has some good pan drippings or gravy to spoon over the top. If you’re going for a vegetarian meal, try serving them alongside roasted vegetables like Brussels sprouts or green beans, or with a hearty mushroom gravy. The garlic and green onions in these potatoes make them flavorful enough to stand on their own, but they really shine when you’ve got something savory to go with them.

Storage Instructions

Store: Keep your leftover mashed potatoes in an airtight container in the fridge for up to 4 days. They might thicken up a bit as they sit, but that’s totally normal with mashed potatoes.

Freeze: These mashed potatoes freeze pretty well for up to 2 months. Just portion them into freezer-safe containers or bags, and make sure to squeeze out any extra air before sealing.

Reheat: Warm them up in the microwave with a splash of extra oat milk, stirring every 30 seconds until heated through. You can also reheat them on the stovetop over low heat, adding a bit more oat milk and stirring frequently to bring back that creamy texture.

Estimated Nutrition

Estimated nutrition for the whole recipe (without optional ingredients):

• Calories: 700-800
• Protein: 15-18 g
• Fat: 4-6 g
• Carbohydrates: 155-175 g

Ingredients

• 1/2 tbsp lemon juice (freshly squeezed for best flavor)
• 1 tsp salt
• 2 lb potatoes (Yukon Gold or russet, cut into 1-inch chunks)
• 8 garlic cloves (minced or smashed)
• 1/2 cup full-fat oat milk (I use Pacific Foods, at room temperature)
• 3 cups water
• 1/4 cup sliced green onions (white and light green parts)
• 1/8 tsp black pepper (freshly ground preferred)

Step 1: Prepare Ingredients and Start Cooking Potatoes

• 2 lb potatoes, cut into 1-inch chunks
• 8 garlic cloves, minced or smashed
• 3 cups water

Cut potatoes into 1-inch chunks and mince or smash the garlic cloves.

Bring 3 cups of water to a boil in a large pot, then add the potato chunks and garlic.

This allows the potatoes and garlic to cook together, which infuses the potatoes with flavor from the start.

Bring back to a boil and maintain a steady simmer.

Step 2: Prepare the Oat Milk Mixture

• 1/2 cup full-fat oat milk, at room temperature
• 1/2 tbsp lemon juice, freshly squeezed

While the potatoes cook, combine the oat milk and lemon juice in a small saucepan.

Let this mixture sit for about 10 minutes—the acid in the lemon juice will slightly curdle and thicken the oat milk, creating a richer texture similar to curdled cream.

This gives the finished mashed potatoes better body and a more luxurious mouthfeel than using plain oat milk alone.

Step 3: Cook Potatoes Until Tender and Warm the Milk

• oat milk and lemon juice mixture from Step 2

Continue simmering the potatoes until they’re completely fork-tender, about 15-20 minutes depending on your pot size and heat level.

While the potatoes finish cooking, gently heat the oat milk mixture over medium-low heat until warm to the touch—don’t let it boil or simmer, as you want to preserve the creamy texture.

This timing means both components are ready at roughly the same moment.

Step 4: Drain and Mash the Potatoes

• cooked potatoes and garlic from Step 3
• warm oat milk mixture from Step 3

Drain the potatoes and garlic thoroughly in a colander—excess water will dilute your mashed potatoes and make them watery.

Return the drained potatoes and garlic to the hot pot and immediately pour in the warm oat milk mixture from Step 2.

Mash with a potato ricer, food mill, or hand masher until you reach your desired consistency.

I prefer using a ricer for the smoothest, fluffiest texture, but a hand masher works perfectly well for a chunkier result.

Step 5: Season and Finish

• 1/4 cup sliced green onions, white and light green parts
• 1 tsp salt
• 1/8 tsp black pepper, freshly ground

Fold in the sliced green onions, salt, and black pepper.

Taste and adjust seasonings as needed—the lemon juice from the oat milk should provide subtle brightness, but you can add more of either salt or pepper to your preference.

Serve warm while the potatoes still have that fluffy, creamy texture.

Simple Oat Milk Mashed Potatoes

Delicious Simple Oat Milk Mashed Potatoes recipe with step-by-step instructions.

Print Recipe Pin Recipe

Prep Time 12 minutes mins

Cook Time 25 minutes mins

Total Time 37 minutes mins

Servings 4

Calories 750 kcal

Ingredients

  

• 1/2 tbsp lemon juice (freshly squeezed for best flavor)
• 1 tsp salt
• 2 lb potatoes (Yukon Gold or russet, cut into 1-inch chunks)
• 8 garlic cloves (minced or smashed)
• 1/2 cup full-fat oat milk (I use Pacific Foods, at room temperature)
• 3 cups water
• 1/4 cup sliced green onions (white and light green parts)
• 1/8 tsp black pepper (freshly ground preferred)

Instructions

 

• Cut potatoes into 1-inch chunks and mince or smash the garlic cloves. Bring 3 cups of water to a boil in a large pot, then add the potato chunks and garlic. This allows the potatoes and garlic to cook together, which infuses the potatoes with flavor from the start. Bring back to a boil and maintain a steady simmer.
• While the potatoes cook, combine the oat milk and lemon juice in a small saucepan. Let this mixture sit for about 10 minutes—the acid in the lemon juice will slightly curdle and thicken the oat milk, creating a richer texture similar to curdled cream. This gives the finished mashed potatoes better body and a more luxurious mouthfeel than using plain oat milk alone.
• Continue simmering the potatoes until they're completely fork-tender, about 15-20 minutes depending on your pot size and heat level. While the potatoes finish cooking, gently heat the oat milk mixture over medium-low heat until warm to the touch—don't let it boil or simmer, as you want to preserve the creamy texture. This timing means both components are ready at roughly the same moment.
• Drain the potatoes and garlic thoroughly in a colander—excess water will dilute your mashed potatoes and make them watery. Return the drained potatoes and garlic to the hot pot and immediately pour in the warm oat milk mixture from Step 2. Mash with a potato ricer, food mill, or hand masher until you reach your desired consistency. I prefer using a ricer for the smoothest, fluffiest texture, but a hand masher works perfectly well for a chunkier result.
• Fold in the sliced green onions, salt, and black pepper. Taste and adjust seasonings as needed—the lemon juice from the oat milk should provide subtle brightness, but you can add more of either salt or pepper to your preference. Serve warm while the potatoes still have that fluffy, creamy texture.