These Roasted Potatoes and Onions are one of the easiest side dishes that’s prepped and ready to bake in 10 minutes. Whether it’s for meal prepping for a busy week or getting dinner on the table quickly, these potatoes pair perfectly with so many mains and will be a favorite among any group you serve them to.
Why I Can’t Stop Making These Roasted Potatoes & Caramelized Onions
I’ve been making these Roasted Potatoes and Onions for years, it’s been an easy side dish staple in our house to add to any menu, whether it’s easy weeknight cooking, summer bbqs, or entertaining. I love adding fresh herbs like thyme and rosemary to my recipe to add even more flavor. The best part is you only need a sheet-pan and a small bowl to prep the potatoes which keeps clean up quick and simple.
I hope you enjoy this easy, crowd-pleasing side dish. It’s a great recipe to give to any beginner cooks at home to teach them some cooking basics and also make a delicious recipe too! Serve it alongside my Citrus Pork Tenderloin and French Onion Chicken Skillet for a hearty meal.
- 5-ingredient sheet-pan side: simple, flavorful roasted potatoes and onions in minutes.
- Customizable herb and spice mix: swap thyme and rosemary for oregano, smoked paprika, or garlic butter. No onion soup mix here!
- Perfect for weeknights, BBQs, or entertaining: Please everyone with this beginner-friendly side that pairs with any main.
Ingredients
- Small red potatoes: Look for potatoes of similar size so they cook at the same rate, or cut into same size chunks. You can also use baby Yukon Gold potatoes. Russet potatoes will yield crisper crusts and fluffier centers, while red potatoes and Yukon golds will have a softer crust, with a creamy center. Use your favorite!
- Vidalia or sweet onions: When these roast they become sweet, jammy, and so addicting.
- Extra virgin olive oil: Fat that helps the potatoes and onions to cook and brown.
- Whole grain mustard: Adds tanginess and acidity to each bite.
- Fresh thyme: You can also use dried thyme here, gives warm herbal flavor.
- Fresh rosemary: Dried rosemary works well too, it adds that floral yet herbal taste we all love.
- Flat-leaf parsley: Adds freshness and a bright green color to garnish.
Get the full recipe in the recipe card below.
How to Make Roasted Potatoes and Onions
Step 1: Prepare the Onions and Potatoes
Preheat the oven to 425°F (220°C). And if desired, line a baking sheet with aluminum foil.
Cut the potatoes in halves or quarters, depending on their size, you want similar sized chunks. Place them on a half sheet pan rated for higher heat (I love my USA pans).
Cut the onions in half, peel them, then slice into ¼-inch-thick slices. Add them to the pan with the potatoes.
Kathleen’s Tip: Many recipes recommend soaking the potatoes in cold water, then drain and dry them before tossing them with the oil mixture. This reduces the potato’s starch and makes it even crisper. But honestly, we love them just the way they are, but feel free to take the time to do this!
Step 2: Make the Seasoning Mix and Toss
Make the seasoning mixture. In a small bowl, whisk together the olive oil, whole-grain mustard, thyme, and rosemary.
Pour the oil and herb mixture over the potatoes and onions. Sprinkle with 1 teaspoon kosher salt and the black pepper, then use your hands to toss everything together until evenly coated. Spreading into a single layer.
Expert Tip: If preferred, you can add it all to a large bowl and toss to coat.
Step 3: Roast and Serve
Time to pop them into the preheated oven to bake (roast) for 50–60 minutes, tossing every 15 minutes or so with a metal spatula (my fish spatula works great for this). This helps the potatoes brown evenly.
Check for doneness. The potatoes should be golden brown and tender inside with a fluffy texture, and the onions should be soft and beginning to caramelize.
Transfer to a serving dish or serve directly from the pan. Sprinkle with chopped flat-leaf parsley and taste for salt, adding more if needed. Serve hot.
Expert Tips
- Don’t overcrowd the pan. Potatoes roast best when they have space. When the potatoes are too close together, they will steam instead of roast. If needed, use two sheet pans.
- Cut potatoes evenly so they cook at the same rate.
- Tossing occasionally during roasting helps create evenly browned, crispy edges.
- Fresh herbs add incredible flavor and an earthy flavor, but dried herbs work beautifully if that’s what you have on hand. You can even add spices too for other added flavors.
- Use a sturdy sheet pan. A good-quality half sheet pan helps the potatoes brown properly and prevents warping at higher heat. If you want super easy clean up, line the sheet pan with parchment paper or foil, but the outsides won’t get as crisp.
Variations
- Make them garlicky: Add in 2 minced garlic cloves or 1 teaspoon garlic powder with the oil mixture.
- Use another type of mustard: Swap the whole grain mustard for Dijon mustard or your favorite.
- Add even more vegetables: I like sliced bell peppers, carrots, or Brussels sprouts for a heartier roasted vegetable mix.
- Sprinkle with some cheese please!: Add freshly grated Parmesan cheese during the last 5 minutes of roasting.
- Flattop Griddle Method: Cook the potatoes and onions on a preheated flattop griddle over medium heat, tossing occasionally, until the potatoes are tender and golden brown (about 25–30 minutes).
- Potatoes: Use what you have! Smaller potatoes work great here, but you could also use fingerling potatoes, or even Russets.
- Dietary Information: These crispy potatoes are naturally vegetarian/vegan, gluten-free, and dairy-free! A delicious side everyone will love!
Storage
Store leftover roasted potatoes in an airtight container in the refrigerator for up to 4 days.
Reheating
When it comes to reheating the potatoes, there are a couple of methods I recommend:
- Oven (best method): Spread potatoes on a sheet pan. Reheat at 375°F for 10–15 minutes until warmed through and crisp.
- Skillet: Heat in a skillet over medium heat with a small drizzle of olive oil, stirring occasionally until hot.
- Air Fryer: Reheat at 375°F for 4–6 minutes, shaking halfway through.
- Microwave (quickest): Microwave in 30-second intervals until warm. Just to caution, the potatoes will be softer with this method but still delicious.
Common Questions
Yes, definitely! They get beautifully caramelized and sweet when roasted.
Yes, we prefer red potatoes for their creaminess, but Yukon gold and russets can also work.
We love rosemary and thyme for the herbs. For spices, it depends on the recipe. Dried herbs, chili powder, cumin, smoked paprika, dill and ground coriander can also be delicious.
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Ingredients
- 2 ½ pounds small red potatoes or small Yukon gold potatoes, may also use Russet potatoes, cut into similar size chunks
- 2 Vidalia sliced or sweet onions
- ¼ cup extra virgin olive oil
- 2 tablespoons whole grain mustard or try Dijon or your favorite mustard
- 1 tablespoon fresh thyme chopped (or 1 teaspoon dried thyme)
- 1 tablespoon fresh rosemary chopped (or 1 teaspoon dried rosemary)
- 1 -2 teaspoons kosher salt
- 1 teaspoon black pepper
- chopped flat-leaf parsley for garnish, if desired
Instructions
- Preheat the oven to 425°F (220°C).
- Prepare the potatoes. Cut the potatoes in halves or quarters, depending on their size. Place them on a half sheet pan rated for higher heat (I love my USA pans). No need to peel, but wash and dry.2 ½ pounds small red potatoes
- Prepare the onions. Cut the onions in half, peel them, then slice into ¼-inch-thick slices. Add them to the pan with the potatoes.2 Vidalia
- Make the seasoning mixture. In a small bowl, mix together the olive oil, whole grain mustard, thyme, and rosemary.¼ cup extra virgin olive oil, 2 tablespoons whole grain mustard, 1 tablespoon fresh thyme, 1 tablespoon fresh rosemary, 1 -2 teaspoons kosher salt, 1 teaspoon black pepper
- Season the potatoes. Pour the oil and herb mixture over the potatoes and onions. Sprinkle with 1 teaspoon kosher salt and the black pepper, then use your hands to toss everything together until evenly coated.
- The potatoes should be golden brown and tender inside, and the onions should be soft and beginning to caramelize.
- Transfer to a serving dish or serve directly from the pan. Sprinkle with chopped flat-leaf parsley and taste for salt, adding more if needed. Serve hot.chopped flat-leaf parsley
Notes
- Oven (best method): Spread potatoes on a sheet pan. Reheat at 375°F for 10–15 minutes until warmed through and crisp.
- Skillet: Heat in a skillet over medium heat with a small drizzle of olive oil, stirring occasionally until hot.
- Air Fryer: Reheat at 375°F for 4–6 minutes, shaking halfway through.
- Microwave (quickest): Microwave in 30-second intervals until warm. Just to caution, the potatoes will be softer with this method but still delicious.
Nutrition
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