Roasted Red Onions, a simple baked onions recipe with garlic and fresh herbs. Great as a simple side dish or as toppings for burgers, bowls, and salads.

roasted red onions on a white plate on a wood table

Love the slightly sweet flavor of red onions? Try roasting them in the oven! Baked onions are incredibly simple to whip up in the oven and taken only 30 minutes with 5 ingredients you likely have on hand. It’s easy, super flexible (add whatever spices you want!), and versatile enough to be eaten as a side dish or a topping for your favorite sandwiches, burgers, salads, and bowls.

👉 Ready to learn how to roast red onions? Let's do it!


🥔 Ingredients you'll need

This recipe requires just a few simple ingredients, including the following:

  • Red Onions: Full of slightly sweet flavor when roasted, red onions are the shining star of this recipe
  • Olive oil: Brings out the flavor of onions when roasted and helps them to crisp when heated
  • Fresh herbs: Any fresh herbs will do, but we love fresh thyme, oregano, sage, and basil (dried herbs can work as well)
  • Seasonings: Garlic, salt, and pepper are the main seasonings in this recipe
  • Recommended tools: sheet pan, knife set, cutting board
whole red onions on a white plate with bowls of olive oil, salt, and pepper
Ingredients: red onions, olive oil, garlic, salt, pepper

🥣 How to make (step-by-step photos)

1️⃣ Step One: Preheat oven and cut onions

First, preheat the oven to 400 degrees F (200 C), then cut the onions.

  • How to cut onions into rounds: To cut rounds slice off the ends of the onion, then make a small slice into the outer layer of the onion and peel it away and slice the onion into rounds.
  • How to cut onions into slices: To cut slices, cut the onion in half and then into thin slices.
sliced red onions on a wood cutting board
Slice red onions

2️⃣ Step Two: Season onions before baking

Next, place the cut onions on a baking sheet and spread them out evenly. Then drizzle them with olive oil and toss with your hands or a spatula to coat them in oil.

Then sprinkle the onions with salt and pepper, and any fresh or dried herbs (or other seasonings you desire).

sliced red onions on a roasting pan before baking
Season onions and add to a roasting pan

3️⃣ Step Three: Roast onions until golden brown

Place the onions on the baking sheet into the oven and roast them until they are golden brown and softened, which takes about 30 minutes.

At about 15-20 minutes into baking, take the onions out of the oven and flip them once to make sure they cook evenly on all sides.

When they’re done, remove them from the oven and place them on a plate to cool. Serve them immediately as a warm side dish, or let them cool and use them as a topping for burgers, salad, or grain bowls.

roasted red onions on a baking sheet after baking
Roast until golden brown

🌿 Flavor ideas

Get creative with the seasonings for your baked onions with these flavor ideas:

  • Add fresh peppers: Combine onions with colorful bell peppers for a roasted veggie combination
  • Rosemary, salt, and pepper: Sprinkle fresh or dried rosemary over the onions, then add some salt and pepper to taste.
  • Thyme, fresh basil, and lemon juice: Add tons of flavor by mixing with thyme, then finishing onions off with some fresh basil leaves and a squeeze of lemon juice.
  • Parmesan and garlic: Baked onions taste great with a mixture of parmesan and garlic. You can also try nutritional yeast for a plant-based cheese alternative.
roasted red onion slices on a white plate on a white table

🧊 How to store

If you have leftover onions, here's how to maintain their quality and flavor in storage:

  1. Refrigerator storage: Store onions in an airtight container in the refrigerator for up to 3-4 days
  2. Freezer storage: For the best taste and texture, we don't recommend freezing roasted onions as they will lose their texture when thawed

♻️ Sustainable kitchen tips

We’re all about going green in the kitchen here at Fork in the Road. Here’s how to make this recipe sustainably:

Take advantage of red onion season. The best time to make this recipe is when red onions are at the height of their growing season. In most parts of the US, onions are in season from early spring to late fall (though because they store so well, they’re typically available year round). Find out when they're in season in your area here.

Grow the onions in your garden. Onions are fairly easy to grow on your own, even in smaller containers. This is a great step toward a sustainable lifestyle – there's no need to travel anywhere when the veggies are growing in your own backyard!


👉 More red onion recipes

Looking for more recipes with red onions? Try our other favorites:

Roasted Red Onions

Roasted Red Onions, a simple baked onions recipe with garlic and fresh herbs. Great as a simple side dish or as toppings for burgers, bowls, and salads.
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Ingredients

  • 4 large red onions
  • 1 tablespoon olive oil
  • 2 cloves garlic, sliced
  • ¼ cup fresh herbs, or 2 tablespoons dried herbs
  • 1 pinch salt and pepper

Instructions 

  • Preheat oven and cut onions: Preheat oven to 400 degrees F (200 C), then cut onions into rounds or slices. To cut rounds slice off the ends of the onion, then make a small slice into the outer layer of the onion and peel it away and slice the onion into rounds. To cut slices, cut the onion in half and then into thin slices.
  • Prep onions for baking: Place onion slices on a sheet pan and combine with a drizzle of olive oil. Once completely coated in oil, season the vegetables with sliced garlic, salt, pepper and any dried or fresh herbs.
  • Roast onions: Bake onions in the oven until soft and brown around the edges, which will take about 30minutes. At about 15 minutes into cooking, toss the vegetables so they brown on all sides. Remove from the oven and serve immediately as a side dish, or let them cool to use as toppings for burgers, salads, and bowls.

Notes

  • Tools needed: sheet pan, knife set, cutting board
  • Prep ahead: Wash and cut onions in advance to reduce prep time before cooking.
  • Leftovers and storage: Roasted onions should be stored in an airtight container in the refrigerator for up to 3-4 days. For best taste and texture, do not freeze and reheat.
  • Nutrition notes: Nutrition information is an estimation and may vary depending on the amount of oil and salt used to roasted the onions. This recipe is vegan and gluten free.

Nutrition Information

Serving: 1serving, Calories: 47kcal, Carbohydrates: 4g, Protein: 1g, Fat: 4g, Saturated Fat: 1g, Polyunsaturated Fat: 0.4g, Monounsaturated Fat: 3g, Sodium: 13mg, Potassium: 71mg, Fiber: 1g, Sugar: 1g, Vitamin A: 317IU, Vitamin C: 8mg, Calcium: 15mg, Iron: 0.3mg