Slow Cooker French Onion Mashed Potatoes Tips, FAQ & printable recipe

Tips for success

For the best texture, cut the potatoes into uniform chunks so they cook evenly. If you prefer a smoother mash, use a potato ricer or an electric mixer after mashing by hand, but be careful not to overwork them.

For extra richness, stir in a few tablespoons of butter or a splash of cream after mashing, though the video's version is delicious as is.

The dish is naturally gluten-free if you use a gluten-free onion soup mix, and it's vegetarian if you use vegetable broth. To make it dairy-free, simply omit any butter or cream. The leftovers are fantastic—they thicken as they sit, so add a splash of broth or water when reheating.

Variations

• Garlic Herb: Add 3 minced garlic cloves and 1 teaspoon dried thyme to the slow cooker with the other ingredients. The garlic will mellow during cooking, and the thyme adds an earthy note that pairs well with the onion.
• Cheesy: After mashing, stir in 1 cup shredded Gruyère or sharp cheddar cheese until melted and creamy. The cheese adds richness and a savory depth that complements the French onion flavors.
• Caramelized Onion Boost: For extra sweet onion flavor, cook 2 additional sliced onions in a skillet with 1 tablespoon butter over medium-low heat for 20 minutes until caramelized, then stir into the mashed potatoes before serving.
• Vegan: Use vegetable broth and a vegan onion soup mix. For a creamy texture, stir in 1/2 cup unsweetened plant-based milk or a few tablespoons of vegan butter after mashing.

Storage and make-ahead

Fridge

Store in an airtight container in the refrigerator for up to 4 days. Stir in a little broth or water when reheating to loosen the texture.

Freezer

Freeze in a freezer-safe container for up to 3 months. Thaw overnight in the refrigerator and reheat gently, adding broth as needed.

Reheat

Reheat in the microwave or on the stovetop over medium heat, stirring frequently, until hot. Add a splash of broth or water to restore creaminess.

Store leftover mashed potatoes in an airtight container in the refrigerator for up to 4 days. The potatoes will thicken as they cool; stir in a little broth or water when reheating to restore the creamy consistency.

The entire dish can be assembled in the slow cooker insert the night before, covered, and refrigerated. In the morning, place the insert in the slow cooker and cook as directed, adding 30 minutes to the cooking time.

You can also cook the potatoes fully, then refrigerate and reheat gently on the stovetop or in the microwave.

Serving ideas

Serve these mashed potatoes as a comforting side to roasted meats like beef, pork, or chicken. They also shine alongside a simple green salad or roasted vegetables for a lighter meal.

The onion strands and beefy flavor make them substantial enough to stand on their own as a main course for lunch.

For a festive presentation, spoon the mash into a serving bowl and drizzle with a little melted butter or sprinkle with fresh chives.

The potatoes are best served hot, straight from the slow cooker, but they also hold well on a buffet if kept warm in the slow cooker on the 'warm' setting.

Frequently asked questions

Recipe card

Slow Cooker French Onion Mashed Potatoes

Prep 10 minCook 4 hTotal 4 h 10 minServes 8

Ingredients

• 3 lb russet potatoes, peeled and cut into 1-inch chunks
• 2 medium yellow onions, thinly sliced
• 1 oz onion soup and dip mix (1 envelope)
• 2 cups beef broth

Instructions

1. Place the peeled and chunked russet potatoes in the slow cooker insert. Scatter the thinly sliced yellow onions over the top. Sprinkle the onion soup mix evenly over the onions and potatoes. Pour the beef broth over everything, making sure the liquid is mostly absorbed by the potatoes and onions but not completely submerged.
2. Cover the slow cooker and cook on LOW for 4 to 5 hours, or on HIGH for 2 1/2 to 3 hours, until the potatoes are fork-tender. The potatoes should be easily pierced with a fork, and the onions should be very soft and translucent.
3. Turn off the slow cooker. Using a potato masher or a large spoon, mash the potatoes right in the insert until they reach your desired consistency. For a chunkier mash, mash briefly; for a smoother mash, mash thoroughly. The onions will break apart and streak through the potatoes.
4. If the mashed potatoes seem too thick, stir in a splash of warm beef broth or water until the desired consistency is reached. Taste and add salt and pepper if needed, keeping in mind that the onion soup mix is already salty.
5. Spoon the mashed potatoes into a serving bowl. Serve immediately while hot, with additional black pepper or a pat of butter if desired.

Contains: celery, gluten, sulfites

Estimated nutrition per serving

Calories

180

Protein

4 g

Carbohydrates

38 g

Fat

1 g

Automatic estimate from the ingredient list, not laboratory-verified.