Spaghetti Squash with Mushroom Rosemary Sauce
This recipe is made with spaghetti squash and topped with a savory mushroom sauce made with caramelized onion, roasted garlic and rosemary. It may be low carb but it is full of flavor.
Table of contents
Why We Love This Recipe For Spaghetti Squash with Mushroom Rosemary Sauce
This stunning meat-free recipe combines the best of both worlds between classic comfort food and new-world style paleo cuisine. You’ll first notice the punch of rosemary on the nose followed by earthy undertones of sauteed mushroom and flavor-forward roasted garlic. The body is balanced by caramelized onions, and structured from low-carb spaghetti squash.
I used the magic roasted garlic puree I made earlier this week, and some of the resulting roasted garlic oil. I am convinced that is the real key to the success of this recipe. The roasted garlic puree acts as a thickener. You’ll just love it.
It takes just about an hour to put this vegan spaghetti squash recipe together, but trust me, it’s worth every minute. It’s a great low-carb alternative pasta when spaghetti squash is in season, and it’s also just a great healthy dinner to make for a Sunday supper.
Ingredient Notes
- Vegetables: Spaghetti squash, onion, mushrooms, and roasted garlic puree
- Extra-virgin olive oil: You could use either extra-virgin olive oil or a roasted garlic oil
- Herbs: Fresh rosemary and either basil or parsley
- Seasonings: Salt and pepper to taste
- Chicken broth: I like to use either No-Chicken Broth or reduced-sodium chicken broth
Step-by-Step Instructions to Make This Spagetti Squash with Mushroom Sauce
Step 1: Bake spaghetti squash
Preheat oven to 375 degrees F. Line a baking sheet with foil or parchment. Cut spaghetti squashes in half lengthwise and scoop out seeds and loose stringy pulp from the center cavity. Place halves cut-side-down on the prepared baking sheet and roast until the squash is soft when you press down on it, 40 to 60 minutes total. Flip it over and try to scrape up the spaghetti-like flesh, to check if it is done. If it is loose and stringy it is done. It shouldn’t be watery. If it doesn’t come up easily, return to the oven and check again in ten minutes.
Step 2: Cook rosemary mushroom sauce
Meanwhile, swirl oil in an unheated large heavy skillet, add onion and place over medium-high heat. Cook, stirring occasionally until the onion is softening and starting to brown, 6 to 8 minutes. Reduce heat to medium-low and continue cooking, stirring occasionally until the onions are soft and brown, 6 to 8 minutes. Add mushrooms, rosemary, salt and pepper. Increase heat to medium-high and cook stirring often until the mushrooms release their juices and the juices evaporate and a brown fond develops on the bottom of the skillet, 4 to 6 minutes. Whisk broth and garlic puree in a small bowl until smooth. Stir into the mushroom and onion mixture and bring to a boil. Cook until the sauce is thickened, 2 to 3 minutes.
Step 3: Serve spaghetti squash
Scrape the spaghetti squash up from the shell with a fork. Serve the squash topped with the sauce and chopped basil or parsley.
FAQs and Expert Tips
Yes. If you cut the spaghetti squash into thick rings crosswise you should be able to get longer squash strands. This is because the squash strands grow around, crosswise, rather than from top to bottom.
When stored correctly, spaghetti squash can last for up to 5 to 7 days. However, since it’s made with other ingredients, I would recommend eating it sooner. Store the dish in an airtight container and place in the fridge for 3 to 4 days.
Yes. You can make the spaghetti squash the day before and store it in the fridge until ready to serve.
Additional Spaghetti Squash Recipes to Try
- I love this Stuffed Spaghetti Squash recipe. It’s low effort and really tasty.
- My Spaghetti Squash with Turkey Sausage Ragu will totally satisfy you when you are craving Italian, but want to keep the meal healthy and veggie-forward.
- Spaghetti Squash Amatriciana–a healthier play on the classic Italian dish.
- This Spaghetti Squash with Chevre and Lemon Thyme Dressing is truly next level.
At Healthy Seasonal Recipes, we specialize in cooking with fresh veggies and creating weeknight meals. Sign up HERE to get more produce-forward dinner ideas for FREE! If you make this recipe, please come back and leave a star rating and review. I would love to hear what you thought! Happy Cooking! ~Katie
PrintSpaghetti Squash with Onions Mushrooms and Rosemary
- Total Time: 1 hour
- Yield: 4 servings 1x
Description
This recipe is made with spaghetti squash and topped with a savory mushroom sauce made with caramelized onion, roasted garlic and rosemary. It may be low carb but it is full of flavor.
Ingredients
- 2 medium spaghetti squash, about 4 1/2 pounds total
- 1 tablespoon plus 1 teaspoon extra-virgin olive oil or roasted garlic oil
- 1 large sweet onion, sliced
- 8 ounces mushrooms, sliced
- 1 teaspoon chopped fresh rosemary
- 3/4 teaspoon salt
- 1/2 teaspoon pepper
- 1/2 cup No-chicken broth or reduced-sodium chicken broth
- 2 to 3 tablespoons roasted garlic puree
- 1/4 cup chopped basil or parsley
Instructions
- Preheat oven to 375 degrees F. Line a baking sheet with foil or parchment. Cut spaghetti squashes in half lengthwise and scoop out seeds and loose stringy pulp from the center cavity. Place halves cut-side-down the prepared baking sheet and roast until the squash is soft when you press down on it, 40 to 60 minutes total. Flip it over and try to scrape up the spaghetti-like flesh, to check if it is done. If it is loose and stringy it is done. It shouldn’t be watery. If it doesn’t come up easily, return to the oven and check again in ten minutes.
- Meanwhile, swirl oil in an unheated large heavy skillet, add onion and place over medium-high heat. Cook, stirring occasionally until the onion is softening and starting to brown, 6 to 8 minutes. Reduce heat to medium-low and continue cooking, stirring occasionally until the onions are soft and brown, 6 to 8 minutes. Add mushrooms, rosemary, salt and pepper. Increase heat to medium-high and cook stirring often until the mushrooms release their juices and the juices evaporate and a brown fond develops on the bottom of the skillet, 4 to 6 minutes. Whisk broth and garlic puree in a small bowl until smooth. Stir into the mushroom and onion mixture and bring to a boil. Cook until the sauce is thickened, 2 to 3 minutes.
- Scrape spaghetti squash up from the shell with a fork. Serve squash topped with the sauce and chopped basil or parsley.
Notes
Make-Ahead: You can make the spaghetti squash the day before and store it in the fridge until ready to use.
- Prep Time: 25 minutes
- Cook Time: 55 minutes
- Category: Main Course
- Method: Oven/Stove Top
- Cuisine: American
Nutrition
- Serving Size: 1 1/2 cups each
- Calories: 236
- Sugar: 15 g
- Sodium: 572 mg
- Fat: 8 g
- Saturated Fat: 1 g
- Carbohydrates: 43 g
- Fiber: 8 g
- Protein: 5 g
This already looks so good but you throw that roasted garlic puree in there and I’m sold!
This looks sooooo amazing, I can’t wait to get a spaghetti squash at the market and try it out!
We love all of the fiber and good veggies in this recipe, plus the lovely, strong rosemary. Thank you!
My goodness that sauce! So rich and delicious yet light! Perfect for Fall dinner!
So amazing and comforting! This will go on our regular rotation.
What causes the sauce to thicken if theres no cornstarch or other thing like it?
Hi Lauren, thanks for stopping by. The sauce thickens from reducing it. The garlic puree gives it a nice silky body too.
Made this tonight and it was excellent! Thank you for the wonderful recipe. Sharing!
I can’t wait to try this recipe, but I have a few picky eaters that run from the table if they see onions in their food. Would it change the outcome of the dish if I puréed the onions after prior to adding the mushrooms,Rosemary, and salt and pepper?
That would be the perfect time to do it. They will be nice and caramelized at that point. Good luck Pamela.
OMG!! Just made this for dinner for meatless Monday. Could not be more pleased with how it turned out other than I wanted so much more!! I’m going to try the mushroom mixture on a toasted flatbread too. The garlic paste is amazing. You’ve got a winner here!
Cyndi, I am so happy to have your feedback. Thank you so much for coming back by to say so.
A fantastic low carb dinner! Please double the portion of sauce for me. I love the lighting too.
I agree about the sauce Angie. It is so savory! Thank you for coming by.
I have never tried squash spaghetti before! Definitely need to make this recipe… curious to know what it tastes like.
Yes give it a try. I love it, and it seems to be more popular than ever. Thanks so much for coming by Thalia.