Oven Roasted Mini Potatoes and Onions

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Make a batch of roasted mini potatoes in the oven. Add onions tossed with mustard and simple seasonings for a perfect potato side dish to make any time of year. Crispy and golden brown, they are the perfect partner to your favorite main dish and will keep warm in the oven while your dinner finishes up.

A white bowl of roasted potatoes.

I love to make roasted mini potatoes with sweet roasted onions several times a month. It is one of my husband's most-requested side dishes ever.

I love to buy the pre-washed mini potatoes they sell at Costco in a big bag, but you can often find smaller mesh bags of mini potatoes at most grocery stores.

This versatile recipe works well with mini red potatoes, baby gold potatoes, and even the red, white, and blue colorful baby fingerling potatoes I find at the farmer's market each summer.

With just 10 minutes prep time, you are going to love how easy it is to make roasted mini potatoes in your oven. Especially when you're grilling your favorite pork or chicken this summer!

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Why This is the Best Recipe

There must be millions of potato recipes on the internet but I think this is the best roasted mini potatoes recipe because:

  1. Easy Prep: Grab a bag of pre-washed mini potatoes and you've already cut down on several minutes of prep time! The rest of the recipe just needs a quick slice and toss.
  2. Flexible: No matter what kind of mini potato you have on hand, this recipe will make perfectly crispy potatoes.
  3. Fresh Flavor: Even if you don't think you like mustard, the ground mustard just gives a little boost to the roasted potatoes. Paired with thyme and crushed red pepper flakes for a little kick, these savory veggies will work with any dinner you have planned.
  4. Keeps Warm Well: When my husband is grilling the main dish, it can be hard to get our timing perfect. I love that these roasted mini potatoes can wait in the warm oven while the meat finishes up on the grill.


The ingredients to make roasted potatoes on the counter.

I almost always have the short list of ingredients sitting in my fridge or pantry:

  • Mini Potatoes: I always grab the big bag of mini potatoes at Costco. They're pre-washed and ready to use. You can buy any kind of mini potatoes your grocery sells, but look for ones that are about the size of a ping pong ball or smaller.
  • Sweet Onion: I recommend something like a Vidalia onion, but any onion will do. I've even made this dish with red onions and they tasted amazing.
  • Whole Grain Mustard: This isn't essential but it adds so much flavor to the roasted potatoes. If you don't like the texture of mustard seeds you could use a smooth Dijon mustard instead.
  • Olive Oil
  • Minced Garlic
  • Dried Thyme
  • Crushed Red Pepper Flakes: If you don't like spice, you can omit this. The red pepper flakes don't make the potatoes "spicy" but they do add a little bit of heat.

Prep the Potatoes on the Roasting Pan

For easy clean up, I always just prep the potatoes right on the baking sheet.

Chop by Size of the Potato:

If your mini potatoes are about ping pong ball sized, cut them in half and add them to the sheet pan. This is the suggested prep for most mini potato varieties.

If your mini potatoes are marble sized tiny potatoes, you don't need to cut them at all.

If your mini potatoes are on the bigger side and similar to a golf ball or bigger, you may want to cut them into quarters.

Chopped potatoes and onions on the baking sheet.

Cut the onion in half and then cut each half into thick strips. Toss them onto the pan.

Add the olive oil and mustard and toss it all together. I just use my hands for this step.

Spread the potatoes into an even layer and then sprinkle them with the dried thyme, crushed red pepper flakes, and salt and pepper.

Baking Instructions

Preheat the oven to 425°F.

Roast the mini potatoes and onions for 20 minutes. Use a spatula to toss the potatoes on the pan. This helps prevent them from burning on the bottom and ensures they get crispy on all sides.

Roast them for an additional 10 - 15 minutes or until they are fork tender and golden brown.

The roasted potatoes on the baking sheet out of the oven.

How to Keep Warm

If you need a little more time for your main dish to finish on the grill, stovetop, or air fryer, you can keep the roasted mini potatoes warm in the oven for up to 15 minutes.

Just turn off the oven and keep the door closed.

The potatoes will continue to cook for another minute or more until the oven starts to cool down, so if you want to keep them warm be sure to stop the oven before they've gotten too dark.

I've found that mini potatoes that were kept warm in the oven for another 5 - 10 minutes are even crispier and fluffier than those just cooked for the initial round. So yummy!


I love the spice blend on these roasted potatoes and it is the one I grab most times I bake them.

However, if you're looking to change things up a bit, you could season the potatoes with one of my favorite spice blends:

Serving Suggestions

Any time you are craving a potato side dish, these roasted mini potatoes would make an excellent choice.

I've served them with all kinds of main dishes including grilled pork tenderloins, air fryer salmon, and as an easy side dish for seasoned chicken tenderloins.

More Potato Recipes

Looking for more potato recipes? Of course you are!

Potatoes are such a budget-friendly way to bulk up a healthy dinner for a hungry family.

You might also love these easy potatoe recipes:

📖 Recipe

A white bowl of roasted potatoes.

Oven Roasted Mini Potatoes and Onions

5 from 2 votes
These crispy roasted mini potatoes with onions, mustard, and simple seasonings are an easy side dish to make any time of year. Pair it with your favorite main dish, they work great with chicken, pork, sausages, and even fish.
TOTAL TIME 45 minutes
PREP TIME 10 minutes
COOK TIME 35 minutes
YIELD 6 servings


  • 1.5 pound bag of mini potatoes red mini potatoes, baby gold potatoes, or mini fingerling potatoes
  • 1 sweet onion sliced
  • 2 tablespoons olive oil
  • 1 tsp minced garlic
  • 1 tablespoon whole grain mustard
  • 1 tsp dried thyme
  • 1/4 tsp crushed red pepper flakes
  • Sprinkle of kosher salt and fresh cracked pepper


  • Preheat the oven to 425°F. Place a large baking sheet on the counter.
  • Cut the mini potatoes in half and add them to the baking sheet. Slice the onion and toss it in with the potatoes.
  • Drizzle the olive oil over the mini potatoes. Add the garlic and mustard to the pan. Use your hands to gently toss all the veggies together so they are evenly coated in oil and seasoning.
  • Spread the mini potatoes into a single layer on the baking sheet. Sprinkle the dried thyme, crushed red pepper flakes, and salt and pepper over the top.
  • Bake for 20 minutes. Use a spatula to toss the mini potatoes and onions.
  • Bake for an additional 10 - 15 minutes or until the mini potatoes are fork tender and a crispy golden brown.
  • NOTE: If you still need a bit of time to finish your main dish, the mini potatoes will keep warm in the oven for 10 - 15 minutes. Just turn the oven off and keep the door closed.
COURSESide Dishes

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The photo collage shows a bowl of roasted mini potatoes and onions ready to be served and the sheetpan of the potatoes about to go in the oven below.

One Comment

  1. 5 stars
    This recipe was very helpful, thank you! I did not use the mustard but used a seasoning salt with garlic and red pepper flakes in it. I mainly used this recipe for the heat setting, time to roast, and the suggestion of prep in the baking pan made for easy cleanup. I also added red and orange sweet peppers for color. These were a hit, thanks again.

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