Caramelized Onion Spaghetti Squash

By Erin AlvarezUpdated Nov 01, 2023, Published Nov 06, 2015

Reader Rating

Total Time 35

Servings 2

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Onions sautéed with butter and olive oil create this scrumptious Caramelized Onion Spaghetti Squash. Mixed with kale and mushrooms for a healthy, colorful meal.

A bowl of spaghetti squash topped with mushrooms, onion and kale.

Boy oh boy, do I have a recipe for you! If you’ve never tried spaghetti squash, this recipe will walk you through exactly how to make it, and show you a really tasty way to flavor it. Spaghetti squash is a low carb alternative to traditional pasta, and it has a semi neutral taste (in my opinion), so it’s easy to flavor with a variety of spices.

WHY THIS SPAGHETTI SQUASH RECIPE IS SO GOOD:

The recipe itself is vegetarian, but you can easily omit the cheese to make it vegan, or add meat (like bacon or sausage) if that’s your thing.
Minimal ingredients are required — you only need 6 or so ingredients
It’s flavored with caramelized onions–aka the BEST way to eat onions–plus a combination of butter and olive oil

Can we PLEASE talk about caramelized onions? Have I professed my love for them before? Maybe, but I’m going to do it again. Gahhhh they’re just perfect, and dare I say THE BEST way to eat onions?! Along with that, roasting and eating spaghetti squash is a great way to enjoy a spaghetti-like dish without using actual pasta. This vegetarian spaghetti squash is sure to please ALL eaters!

spaghetti squash

HOW TO COOK SPAGHETTI SQUASH

FIRST: Slice the spaghetti squash in half length-ways, then brush both sides of it with olive oil and place it cut-side down on a a parchment-lined baking sheet.

Note: This caramelized onion spaghetti squash should come together in less than an hour, give or take depending on the size of your squash. The larger the squash, the longer it’s going to take to roast. Mine was not very big—maybe 2-3 lb.—and it fed both my brother and I, so you definitely don’t need anything too too big, and as for the cheese, it’s completely optional–seriously, your call!

caramelized onion spaghetti squash | thealmondeater.com

SECOND: Once the squash is roasted, you’ll take it out of the oven and carefully use a fork to remove the “spaghetti”. While the squash is roasting, you should make the caramelized onion mixture. Then, add the cooked squash to the skillet with the caramelized onions, making sure to stir everything together. In addition to the onions, the squash will be flavored with a little rosemary and cheese if you opt to use it, plus kale, mushrooms and plenty of salt and pepper. It’s so simple yet so tasty as well!

caramelized onion spaghetti squash | thealmondeater.com

OTHER VEGETARIAN DINNER RECIPES

4.76 from 53 votes

Caramelized Onion Spaghetti Squash

By Erin Alvarez

Servings:

Prep: 10

Cook: 25

Total: 35

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Onions sautéed with butter and olive oil create this scrumptious Caramelized Onion Spaghetti Squash recipe, complete with mushrooms!

Ingredients

▢ 1 2-3 lb. spaghetti squash
▢ 1/4 cup olive oil
▢ 2 tbsp butter, I used dairy free
▢ 2 medium yellow onions, peeled and sliced into longer strips if possible
▢ 1 1/2 cup mushrooms
▢ 1 cup kale
▢ 1/4 tsp rosemary, I used fresh, but dried would work too
▢ Salt and pepper to taste
▢ Optional: sprinkle of parmesan cheese

US Customary - Metric

Instructions

Preheat oven to 350°.
Slice squash in half, remove seeds and place on baking sheet.
Brush 2 tbsp olive oil on both sides of the squash (1 tbsp per half) and then place face down in the oven.
While squash is roasting, melt butter and last 2 tbsp oil over medium-high in a large skillet.
Add onions to skillet, stirring occasionally. After 5 minutes, add mushrooms.
After approximately 10 minutes, the onions should start to caramelize. If they look like they're burning at all, add an extra tablespoon of oil.
Add kale to skillet and continue to stir everything together until onions turn a nice golden brown color.
After 45 minutes, remove squash from oven and allow 10 or so minutes for it to cool off.
Once slightly cooler, use a fork to remove "spaghetti" from squash and place in a skillet; add rosemary, salt and pepper and stir everything together.
Add parmesan cheese if you wish and enjoy!