Oven Roasted Red Onions

Tender with caramelized edges, these sweet Roasted Red Onions are a delicious and versatile side dish that go with almost anything. 

Roasting is our absolute favorite way to add flavor to vegetables. And once you have the technique down, you can use it on everything from Roasted Mini Peppers to Roasted Broccoli and Carrots to Roasted Celery Root.

Jump to:

• Why Make This Recipe
• 🥗 Ingredients
• 🥣 Step-by-Step Instructions
• 🧐 Recipe FAQs for Roasted Red Onions
• 👩‍🍳 Expert Tips for Oven-Roasted Onions
• Other Roasted Vegetable Recipes
• 📖 Recipe
• More About Molly
• Comments

Why Make This Recipe

• With minimal prep time, these onions are an easy side dish.
• Only 4 ingredients
• Vegan, dairy-free, and gluten-free, so perfect for almost any eater
• Delicious with grilled meats, but go well with so many other dishes

🥗 Ingredients

• Red Onions: We love the sweet flavor of roasted red onions, but you can replace with yellow or white onions as well. If you want something that has the sweetness of a red onion, try a Vidalia onion instead. 
• Olive Oil: We are roasting at a high temperature, so olive oil is a good choice because of its high smoke point. You could replace this with a different oil, such as avocado oil or sunflower oil, but be sure to look for something with a similarly high smoke point. 

🥣 Step-by-Step Instructions

Let’s talk about how to roast red onions. First, preheat oven to 450 degrees Fahrenheit. Cut 1 ½ pounds of red onions in half, then place onions cut side down and slice off each end. Peel off papery skin, then cut onions in ¾-inch-thick wedges.

Put onion wedges in a large bowl, and add 2 tablespoons olive oil, ½ teaspoon kosher salt, and ½ teaspoon freshly ground black pepper. Toss until onion slices separate a bit and are evenly coated in oil.

Line a sheet pan with parchment paper or nonstick foil. Distribute onions on the sheet pan in a single layer.

Roast for 15 minutes, then stir. Roast for an additional 10-15 minutes, depending on how caramelized you want the edges of your onions to be. 

Garnish with parsley if desired. Store leftovers in an airtight container in the refrigerator for up to 5 days. 

🧐 Recipe FAQs for Roasted Red Onions

👩‍🍳 Expert Tips for Oven-Roasted Onions

This red onions recipe is super versatile when it comes to other flavors. You can add herbs like rosemary or thyme to the onions, or season them with spices like chili powder, garlic salt, curry powder, or smoked paprika. You can also add a splash or two of balsamic vinegar to your sliced red onions to make balsamic roasted onions. 

Don’t crowd the onions onto a small baking sheet—they need to be distributed in a single layer so that they caramelize rather than steam. 

Make sure to look for onions that are firm with dry skin, and avoid onions that have soft spots. (That said, if you get a onion with a brown spot, you can cut that out when you are slicing the onion into wedges.)

Using nonstick foil or parchment paper on your baking sheet makes cleanup easy. Plus, the onions won’t stick to your pan. 

You could try this recipe with shallots instead of red onions. Just peel, cut in half, and roast as directed above. You may find the shallots need less time to roast. 

Roasted bell peppers and onions are a delicious combination. Just combine this recipe with my Roasted Mini Peppers recipe for an easy, but flavorful side dish. Roasted red onions and potatoes is another classic pairing.

Now that you have your oven roasted red onions, what to serve them with? They are delicious for a summer BBQ, as they go really well with grilled meats. But you can also stir them into a pasta dish, like this Creamy Mascarpone Pasta, or use them as a topping for sandwiches. They are also perfect in grain bowls, like in this Crispy Tofu Buddha Bowl recipe. And try serving on a charcuterie board with cheeses and cured meats. 

Other Roasted Vegetable Recipes

As we said, we LOVE roasting vegetables as it’s the best way to bring out their flavor. Here are some favorite recipes:

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