Name: Roasted Potatoes and Onions with Herbs and Mustard Recipe
Prep time: 15 min
Cook time: 55 min
Total time: 1 h 10 min
Cuisine: American
Ingredients: 2 ½ pounds small red potatoes (or small Yukon gold potatoes, may also use Russet potatoes, cut into similar size chunks); 2 Vidalia onions (sliced or sweet onions); ¼ cup extra virgin olive oil; 2 tablespoons whole grain mustard (or Dijon or 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 (optional)

Jump to Recipe· 3.8 from 77 reviews

If you love the cozy feeling of a warm, hearty side dish that bursts with flavor, you are going to adore this Roasted Potatoes and Onions with Herbs and Mustard Recipe. Imagine tender, golden potatoes mingling with soft, caramelized onions, all enveloped in an aromatic mix of fresh herbs and tangy mustard. It is the perfect balance of rustic and refined, a dish that transforms simple ingredients into a showstopper worthy of any meal. Every bite brings comfort and a little excited smile because it’s packed with layers of texture and seasoning that dance on your palate.

Ingredients You'll Need

A top view of several small clear glass bowls arranged on a white marbled surface with a green and white checkered cloth on the side. The largest bowl in the center holds quartered red potatoes with smooth red skin and pale yellow inside. To the right, a medium clear bowl contains sliced white sweet onions with a soft texture. Above the potatoes is a small glass cup filled with golden extra virgin olive oil, with a clear handle. To the left, smaller glass bowls hold fresh green rosemary and fresh thyme herbs. Below are two tiny white bowls, one filled with coarse black pepper and the other with white kosher salt. At the upper left corner, another small clear bowl holds a brown and yellow textured whole grain mustard. All items are neatly arranged on the smooth white marbled surface. Photo taken with an iphone --ar 4:5 --v 7

The beauty of this dish lies in its simplicity; the ingredients are modest but essential, each playing a vital role in building the dish’s charm in flavor, texture, and even color. Gathering fresh herbs and good-quality mustard really elevates this humble side into something special.

2 ½ pounds small red potatoes: Their waxy texture helps them hold shape and offers a creamy bite inside once roasted.

2 Vidalia onions: Sweet onions that caramelize beautifully and add a natural sweetness.
¼ cup extra virgin olive oil: Provides richness and aids in the crisping and roasting process.
2 tablespoons whole grain mustard: Adds a pleasant tang and a little texture with mustard seeds, but Dijon or your favorite mustard can work just as well.

1 tablespoon fresh thyme: Offers a subtle earthiness; dried thyme is a convenient alternative.
1 tablespoon fresh rosemary: Brings fragrant, woodsy notes that pair perfectly with potatoes.
1 to 2 teaspoons kosher salt: For seasoning and enhancing flavors.

1 teaspoon black pepper: Adds gentle heat and depth.
Chopped flat-leaf parsley: For garnish, to bring freshness and color to the finished dish.

How to Make Roasted Potatoes and Onions with Herbs and Mustard Recipe

Step 1: Preheat and Prepare the Vegetables

Start by setting your oven to a high 425°F, which is perfect for roasting potatoes until they're crisp outside and tender inside. Wash your potatoes thoroughly and chop them into halves or quarters to ensure they roast evenly. There’s no need to peel them because the skins add texture and nutrients. Slice your Vidalia onions into thin, ¼-inch slices after peeling and halving; this will allow them to soften and caramelize beautifully alongside the potatoes.

Step 2: Mix the Herb and Mustard Seasoning

In a small bowl, whisk together the olive oil, whole grain mustard, freshly chopped thyme, and rosemary. This mixture is the heart of your flavor here — the olive oil helps everything roast beautifully, the mustard adds a delightful tang paired with grainy texture, and the herbs infuse the dish with aromatic vibrancy.

Step 3: Toss Everything Together

Place the cut potatoes and onions into a sturdy roasting pan or half sheet pan suitable for high heat. Drizzle your herb and mustard mixture evenly over the vegetables. Add 1 teaspoon of kosher salt and the black pepper, then use your hands to toss everything well. This step ensures every piece is coated with love, making sure the flavors latch on and the potatoes crisp up wonderfully.

Step 4: Roast and Toss Periodically

Slide the pan into your preheated oven and roast for 50 to 60 minutes. About every 15 minutes, grab a metal spatula to gently toss the potatoes and onions. This crucial step promotes even browning and prevents sticking, turning your simple ingredients into golden bites filled with flavor and soft caramelized onions throughout.

Step 5: Finish and Garnish

When the potatoes are fork-tender and beautifully golden, and the onions have softened to a sweet caramelized finish, your dish is ready to come out of the oven. Transfer to a serving dish or serve straight from the pan for a rustic touch. Sprinkle with chopped flat-leaf parsley to brighten the dish visually and add a fresh herbal note. A quick taste check to adjust the salt completes the final flourish before serving.

How to Serve Roasted Potatoes and Onions with Herbs and Mustard Recipe

A green bowl is filled with golden brown roasted potato pieces with red skin. The potatoes are cut into uneven chunks, showing crispy, browned edges and soft, white inside. Small green herb bits are sprinkled over the potatoes. The bowl is placed on a white marble surface. Nearby, there is a gold spoon on the left side and fresh green herbs on the right side. A white and green checkered cloth is in the background. photo taken with an iphone --ar 4:5 --v 7

Garnishes

Fresh parsley is your go-to garnish for this recipe because it adds a fresh, vibrant pop of color and flavor right before serving. You could also experiment with finely chopped chives or a sprinkle of parmesan cheese for an added savory touch. Lemon zest is a wonderful hint of brightness that lifts the whole dish effortlessly.

Side Dishes

This Roasted Potatoes and Onions with Herbs and Mustard Recipe pairs beautifully with grilled meats like chicken or steak, complementing their smoky flavors. It also works wonderfully alongside roasted vegetables or a crisp green salad for a lighter meal. The versatility means it fits into weeknight dinners and weekend feasts alike.

Creative Ways to Present

For a fun twist, serve these roasted gems inside a hollowed-out baked potato or stuffed bell peppers for an elegant presentation. You could also layer them as a hearty side in a serving bowl topped with a dollop of sour cream or Greek yogurt mixed with fresh herbs. This makes the dish feel a little more special while keeping it comforting and approachable.

Make Ahead and Storage

Storing Leftovers

If you find yourself with leftovers of this Roasted Potatoes and Onions with Herbs and Mustard Recipe, store them in an airtight container in the refrigerator. They will stay fresh for up to 3 to 4 days, making for quick, flavorful meals or easy additions to salads or bowls throughout the week.

Freezing

You can freeze the roasted potatoes and onions, but keep in mind that the texture might soften slightly upon thawing. For best results, freeze the cooled dish in a sealed freezer-safe container for up to 2 months and thaw overnight in the fridge before reheating.

Reheating

To reheat and regain some of that fresh-out-of-the-oven crispness, pop the leftovers in a hot oven at 400°F for about 10-15 minutes. Avoid microwaving if possible, as it tends to make the potatoes mushy. Using the oven helps keep the herbs fragrant and the potatoes delightfully crispy.

FAQs

Can I use other types of potatoes for this recipe?

Absolutely! While small red or Yukon gold potatoes are ideal for their texture, Russet potatoes cut into similarly sized chunks also work beautifully. Just be mindful they can be a bit fluffier and less waxy.

Is it necessary to toss the vegetables every 15 minutes while roasting?

While not absolutely mandatory, tossing helps ensure the potatoes brown evenly and prevents the onions from sticking to the pan. It’s highly recommended for the best flavor and texture.

Can I make this recipe vegan?

Yes! This recipe is naturally vegan-friendly, using olive oil and herbs without any animal products. Just make sure your mustard and any optional garnishes align with your dietary preferences.

How can I make this dish ahead for a party?

You can prepare everything up to the point of roasting, then cover and refrigerate the vegetables tossed with oil and herbs. Roast just before serving for fresh-cooked brilliance.

What can I substitute for fresh herbs if I don’t have any on hand?

Dried herbs work well, just use about a third of the amount compared to fresh herbs since they are more concentrated. Thyme and rosemary powders or blends will still give you great flavor.

Final Thoughts

This Roasted Potatoes and Onions with Herbs and Mustard Recipe has become one of those dishes that feels like a warm hug after a long day. It’s joyful in its simplicity, yet special enough to impress guests and family alike. I can’t wait for you to try it and see for yourself how these humble ingredients transform into something truly memorable. Happy roasting!

Roasted Potatoes and Onions with Herbs and Mustard Recipe

Ingredients You'll Need

How to Make Roasted Potatoes and Onions with Herbs and Mustard Recipe

Step 1: Preheat and Prepare the Vegetables