Slow Roasted Onions

These slow roasted onions are an easy, flavorful, budget-friendly side dish that can be prepared in advance. They’re perfect for the holidays or whenever you’re craving some sweet, caramelized oniony goodness. This dish is gluten-free, vegan, and paleo diet-friendly.

Main ingredients & substitutions

You can use any type of onions you like for this recipe. Sweet onions or red onions are my top choices, but any variety will work.

Dried thyme gives these onions a lovely aroma and warm, cozy flavor. You can substitute dried rosemary instead if you prefer.

I used extra virgin olive oil in this dish but you can substitute any other neutral oil you prefer.

Roasted onions in a white serving bowl.

How to make them

These onions do take a while to make, but they’re really easy and can be prepared in advance, which makes them the perfect addition to a holiday feast or any other special occasion meal. These baked onions are a great, easier alternative to caramelized onions, which are traditionally made on the stovetop and require a lot of stirring and attention to ensure they don’t burn.

To make these roasted onions, start by preheating the oven to 300 degrees Fahrenheit, then roughly chop the onions.

Raw chopped onions on a white cutting board.

Add the chopped onions, thyme, olive oil, salt, and pepper to a large baking dish (mine is 9 x 13 inches, but any similar size is fine). Use your hands or a spoon to toss the onions, ensuring they’re evenly coated with oil.

Onions in a glass baking dish.

Bake at 350 degrees Fahrenheit for one hour, then mix thoroughly before continuing to bake for one additional hour or until the onions are golden brown around the edges.

Cooked onions piled in a white bowl.

Serve hot or store them in an airtight container in the fridge for up to three days, then reheat before serving.

Optional addition

Bell peppers are a delicious addition to this dish. Any color is fine. Just remove the seeds and roughly chop the peppers, then add them to the baking dish along with the other ingredients.

What to serve them with

Slow Roasted Onions

These slow roasted onions are an easy, budget-friendly, flavor-loaded side dish that can be prepared in advance. This dish is gluten-free, vegan, and paleo diet-friendly!
Course Side Dish
Cuisine American
Prep Time 5 minutes
Cook Time 2 hours
Total Time 2 hours 5 minutes
Servings 9
Calories 56kcal

Ingredients

  • 4 cups roughly chopped onions (any type of onion is fine)
  • 2 tablespoons extra virgin olive oil
  • 1/2 teaspoon dried thyme
  • 1/8 teaspoon salt
  • 1/8 teaspoon black pepper

Instructions

  • Preheat the oven to 300 degrees Fahrenheit.
  • Roughly chop the onions.
  • Add the chopped onions, extra virgin olive oil, dried thyme, salt, and pepper to a large baking dish (mine is 9 x 13 inches but any similar size is fine).
  • Toss the ingredients with your hands or a spoon, ensuring that the onions are coated with oil.
  • Bake at 300 degrees Fahrenheit for 1 hour, stir, then continue to bake for 1 additional hour or until they’re slightly golden brown around the edges.

Notes

  • Serve these slow roasted onions hot or store them in an airtight container in the fridge for up to three days, then reheat before serving.

Nutrition

Serving: 0.33Cup | Calories: 56kcal | Carbohydrates: 7g | Protein: 1g | Fat: 3g | Saturated Fat: 1g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 2g | Sodium: 35mg | Potassium: 105mg | Fiber: 1g | Sugar: 3g | Vitamin A: 4IU | Vitamin C: 5mg | Calcium: 18mg | Iron: 1mg