3-Ingredient Slow Cooker Onion Butter Potatoes

These slow cooker onion butter potatoes need only three ingredients and a few minutes of hands-on work. Small red potatoes cook until tender in melted butter and onion soup seasoning, creating a savory coating that clings to every piece. Serve them as an easy side for roast meat, chicken, or a holiday ham.

Serving bowl filled with slow cooker onion butter potatoes — Red potatoes, butter, and onion soup mix make a deeply savory side dish.

Recipe at a glance

Servings: 6
Prep time: about 10 minutes
Cook time: 4–5 hours on low or 2–3 hours on high
Method: slow cooker

Just three ingredients

3 pounds small red potatoes, scrubbed and quartered
½ cup (1 stick) unsalted butter, melted
2 packets dry onion soup mix, about 1 ounce each

Choose potatoes of similar size and cut them into roughly equal pieces. Leaving the red skins on adds color and helps the pieces hold together. Onion soup mixes vary in saltiness, so the recipe does not need extra salt before serving.

Small red potatoes, some quartered on a cutting board — Quarter the potatoes into even pieces so they cook at the same rate.

How to make slow cooker onion butter potatoes

1. Prepare the potatoes

Rinse the potatoes under cool water and scrub away any soil. Dry them, then cut each into quarters. If some potatoes are much larger than others, cut those into additional pieces. Put the potatoes in the slow cooker in an even layer. Lightly buttering the crock first is optional and can make cleanup easier.

2. Mix the butter and seasoning

Melt the butter until it is liquid but not browned. Stir both packets of dry onion soup mix into the butter, making sure the dried onion flakes are evenly moistened. This quick mixture carries the seasoning over the potatoes more evenly than sprinkling the powder directly into the cooker.

Melted butter stirred with dry onion soup mix in a glass measuring cup — Stir the onion seasoning into melted butter before coating the potatoes.

3. Coat and cook

Pour the seasoned butter over the potatoes. Toss gently until the pieces are glossy and the onion flakes are distributed throughout. Cover and cook on low for 4–5 hours or high for 2–3 hours. They are ready when a fork slides easily into the center of a potato piece. During the last hour, stir once or twice to redistribute the butter and seasoning. Every slow cooker heats a little differently, so begin checking near the early end of the time range.

Tender onion butter potatoes being stirred in a slow cooker — A gentle stir near the end coats the potatoes with the onion butter.

4. Serve

Turn off the slow cooker and gently fold the potatoes through the sauce one final time, scraping up the flavorful onion bits from the bottom. Spoon them into a serving bowl and drizzle over any remaining butter mixture. Serve hot alongside meatloaf, pot roast, baked ham, or grilled chicken. A green vegetable or salad balances the rich side dish.

Helpful variations and leftovers

Yukon Gold potatoes can replace the red potatoes for a creamier interior. Salted butter works too, but taste before adding any salt because the soup mix is already seasoned. If the cooker runs hot and the edges darken too quickly, switch to low and stir gently. For a larger gathering, an extra pound of potatoes can be paired with roughly half a packet more soup mix and one or two extra tablespoons of butter; avoid filling the slow cooker so full that it cooks unevenly.

Refrigerate cooled leftovers promptly in a covered container for up to 3–4 days. Reheat them in a skillet over medium heat with a small amount of butter, turning occasionally until hot and crisp at the edges. They are especially good beside eggs for breakfast.