Tomato Mushroom Spaghetti Squash is a delicious Whole30 recipe. Whether you eat Whole30 or not, it’s a light, healthy alternative to pasta.
I completed a cycle of the Whole30 this past spring. Surprisingly, it was much easier than I thought it would be. I figured it would be a good time to “reset” my body before summer. The amount of vegetables I ate, and sneakily feed to the family, just about doubled. Doing so kept me feeling full, and for a much longer time. Even before Whole30, I had been making spaghetti squash as a gluten-free alternative to pasta. My daughters surprised me when then told me they actually preferred the squash to regular pasta. So, I’ve been buying at least 2 spaghetti squashes every week for the four of us. Sometimes I serve it with Pesto, or my Summer Pasta Sauce.
For the tomato mushroom spaghetti squash, the cooked spaghetti squash was sauteed with fresh vegetables.
Garden tomatoes, mushrooms, onions, and for a Mediterranean spin, some fresh basil. I used a mixture of both halved cherry tomatoes, and a heirloom tomato from my garden. Once you’ve cooked the squash, the “sauce” is just a quick stir-fry. If you’re not concerned about dairy, a sprinkle of parmesan adds another dimension of flavor. Extra bonus: without the cheese, this dish is vegan. A handful of toasted pine nuts, a pinch or two of red pepper flakes and some basil, cut chiffonade, give it lots of flavor without extra calories.

- 2 spaghetti squash cooked "al dente", about 6 cups.
- 2 cups diced tomatoes
- 4 cloves garlic minced
- 8 ounces mushrooms sliced
- 1/3 cup chopped onions or shallots
- 1/4 cup toasted pine nuts
- small handful of fresh basil cut chiffonade
- 3 Tablespoons olive oil
- Kosher salt and black pepper to taste
- Pinch of red pepper flakes if desired
- Optional: Parmesan cheese
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Cook spaghetti squash. (see notes) When cool enough to handle, slice in half, remove seeds and stringy bits and shred with 2 forks. Set aside squash.
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In a large saute pan, heat oil over medium heat. Add onions and mushrooms, stirring constantly, about 3-4 minutes. Add garlic and stir another minute or 2, just until fragrant. Don't let garlic brown.
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Add tomatoes and continue stirring.
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Add cooked spaghetti squash and toss until squash is hot and vegetables are evenly distributed.
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Toss with fresh basil and toasted pine nuts. Season to taste with kosher salt, pepper and a pinch of red pepper flakes if desired.
I hope you enjoy this tomato mushroom spaghetti squash!
Cooking notes: You can prepare the spaghetti squash a couple of ways. If I have time, I bake it in the oven. If I’m pressed for time, I just microwave the halves for 6-8 minutes, depending on the size of the squash. To microwave, pierce the squash with a knife several times to release steam. Microwave the squash whole for a few minutes until it’s soft enough to cut into. Then either slice it either horizontally, or vertically. Scoop out the seeds and stringy bits, then continue microwaving, a few minutes at a time, by placing the halves in a shallow microwaveable dish with a little bit of water. This should take a total of 10 minutes.
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Mimi says
Love it! Glad your kids enjoy the squash – that’s really wonderful! I just made something similar but included meatballs for my husband. Love the addition of pine nuts!
Cynthia says
Meatballs would be a nice addition for a meat-loving husband! I have to admit, mine needs meat, so this is a side-dish, not a main course for him.
Melissa @ Treats With a Twist says
Ok, I need to go buy a new basil plant ASAP! This looks fantastic!
Gina @ Running to the Kitchen says
When I did a Whole30 (years ago) I sweat I survived off “noodle” dishes just like this. This is a lovely twist for summer!
Cynthia says
thank you Gina!
Julie @ Willow Bird Baking says
This looks delicious and so healthy!
Cynthia says
Thank you Julie!
christina conte says
I have to admit, I haven’t had spaghetti squash in donkey’s years, but I’ve never had it as a substitute for pasta. This recipe sounds wonderful, might just have to give this a try!
Cynthia says
well, you know we don’t eat much “real” pasta…so this is a great substitute!
Kathy says
I just bought the Whole30 book. How well do you do on it? Did you lose 30 pounds? When I start I am definitely making this recipe
Cynthia says
Hi Kathy…no I didn’t lose 30 pounds…I only need to lose about 8-10 pounds. I mostly do it because it’s very similar to the Wheat Belly Diet, and Paleo diets. I hate the word “diet” though, because it sounds like something temporary. I try and stay away from wheat and grains as much as possible. I just feel better when I don’t eat them…more clear headed and not so bloated. Dr. Davis from The Wheat Belly, really explains the medical reasons for avoiding grains. I’m about 80% compliant! Let me know how you like the spaghetti squash!
Deb says
For baking a spaghetti squash how do you cut that hard squash in half? I can never get anywhere half and half and my knives take forever to do that.
I’d use and bake more of the hard squashes if they weren’t so hard to cut in half.
Cynthia says
I’ve done it a few ways. Sometimes I’ll ask my husband to slice it for me. What i’ve found the easiest/fastest way is to give it one good stab, then microwave it for 5-7 minutes until it’s easier to slice. Or if I have plenty of time, I just bake it until it’s soft enough to cut then finish roasting it.
Depends on how much time you’ve got. I also will tend to make 2, so I have an extra one ready for a meal later in the week. someone needs to start packaging pre-cooked/shredded spaghetti squash, right?
j turneroan says
Buy Yourself a Spirelletti from Amazon , it takes a summer Zucchini or squash, and you put it in a rotisserie looking device , and it turns the zucchini or squash in to either thin spaghetti, or the thicker like a vermicelli, also used with cucumbers makes either ribbons, or large pinwheels , I was a twice to three times a week pasta person, I’ll never go back
Cynthia says
I have heard about those spiralizers and have only hesitated because of the storage of another gadget…but I really need to! Thanks!
Rachel @ Baked by Rachel says
My family would love this! Such a great dinner idea for the new year!
Marye says
Oh wow, this looks absolutely fantastic!
Cynthia says
Thanks Marye! <3
Tammy says
I am a big big fan of spaghetti squash and this dish 😀 I’ve heard so much about Whole30 but never actually looked into it. I’m going to have to check it out soon.
Cynthia says
I’ve done two rounds of it. It’s definitely strict, so my husband’s not a fan. But for his portion, I top it with grated parmesan and he’s happy!
Taylor Kiser says
This looks so delicious! Would love to have for dinner soon! Totally wouldn’t miss the pasta and this is so much more healthier!
Cynthia says
We try to sub spaghetti squash as much as possible for pasta! It’s so flavorful, no one really misses it!
Megan says
I used 2 spaghetti squashes as instructed but I felt like I ended up with too much spaghetti squash and it wasn’t as flavorful and I would’ve liked. I will try to increase the ratio of vegetables to spaghetti squash next time–also I think it would be great to have spinach leaves thrown in there too!
Cynthia says
I think it depends on the size of your spaghetti squash. I should have weighed them (which I’ll do next time), because 2, 1 1/2 pound squashes would yield a lot less than 2, 2 pound squashes.
Jane G says
Just made this, currently eating it and it’s amazing! Doing Whole 30, so no parm for me. Im going to pull a classic recipe commenter move and tell you what I did differently. One, I used fire roasted canned diced tomatoes instead of fresh, because I had them. I added diced Zucchini, again because I had it, I left out the pine nuts, because I didn’t have them and I don’t really eat them so I didn’t want to buy a bunch to sit in my pantry for years to come until I eventually throw them out. Dish is great on its own but would be awesome with some chicken or meatballs. I might double the mushrooms next time, but I reeaaalllly like mushrooms. The amount of mushrooms in it is totally fine for normal eaters, mushrooms are my thing though so I will add more next time.
Jane G says
Oh, I also only used half of one spaghetti squash, 2 spaghetti squashes yeilds a LOT of ‘spaghetti’ I had more than enough from one half of a squash.
Cynthia says
Hi jane, I think it depends on the size of the spaghetti squash, which is why I put a cup reference. I just made it this past weekend and my daughters (22 and 16) and I ate it in one sitting.
My youngest daughter said, “why did you only cook ONE spaghetti squash?”
Cynthia says
You could totally use canned tomatoes, I just use fresh because I usually have a lot of them in the summer. Any kind of protein would work really well, chicken, sausage or even grilled shrimp. I’m with you, the more mushrooms the merrier!
Asia says
This came out delicious! Thank you for the recipe.
Cynthia says
Glad you liked it! You can always add cooked chicken if you need a little more protein!