I make this Pesto Spaghetti Squash with Tomatoes when my garden is overflowing with basil and I have a batch of homemade pesto ready. My husband jokes and calls it “squashta” because I sometimes prepare the same combination with pasta instead of squash.
Pesto Spaghetti Squash with Tomatoes
Spaghetti squash tossed with fresh pesto and diced tomatoes makes a bright, seasonal dish that works equally well as a light main or a summer side. The strands of spaghetti squash act like a pasta substitute—lower in carbohydrates but excellent at holding sauce—and the bright basil pesto and sweet tomato pieces add fresh flavor without much effort. If you prefer a heartier plate, add grilled chicken or sautéed shrimp on top for protein.
Why this recipe works
This recipe is simple, uses just a few ingredients, and highlights quality produce. Fresh basil and garlic blended with olive oil and Parmigiano-Reggiano yield a fragrant pesto that needs only a handful of spaghetti squash strands and chopped tomato to make a satisfying dish. The microwave method keeps the kitchen cool and speeds up preparation, but roasting the squash in the oven brings deeper caramelized flavor if you prefer.
Ingredients
This easy recipe uses just a few pantry and garden staples:
- 1 medium spaghetti squash
- About 15 large fresh basil leaves (or more to taste)
- 1 small clove garlic
- 1/4 cup extra virgin olive oil
- 3 tablespoons grated Parmigiano-Reggiano (plus extra for serving)
- Kosher salt and freshly ground black pepper, to taste
- 1 medium tomato, diced
How to make Spaghetti Squash with Pesto
- Cut the spaghetti squash in half lengthwise and scoop out the seeds and stringy fibers with a spoon.
- Pierce the squash skin a few times to allow steam to escape, then place the halves cut-side up (or cut-side down if preferred) in a microwave-safe dish and cover loosely.
- Microwave on high for about 8–9 minutes, or longer for a larger squash, until the flesh is tender and the skin yields to pressure. (See the microwave section below for tips.)
- Remove the squash from the microwave and use a fork to scrape the flesh into strands into a large bowl—these will look like spaghetti strands.
- While the squash cooks, make the pesto: in a small blender or food processor, pulse the basil leaves, garlic, grated Parmesan, salt, and pepper. With the motor running, drizzle in the olive oil and blend to a smooth but not over-processed pesto.
- Toss about two cups of the cooked spaghetti squash with a generous amount of pesto (reserve any extra squash for another recipe). Gently fold in the diced tomato and taste for seasoning; add more salt and pepper if needed.
- Serve warm, sprinkled with additional grated cheese if desired. Add grilled chicken or sautéed shrimp for a protein boost, or toss in toasted pine nuts for texture.
How to microwave spaghetti squash
The microwave is a quick way to cook spaghetti squash without heating the oven. After halving and seeding the squash, place it in a microwave-safe dish and cover. Microwave 8–9 minutes on high, checking tenderness with a fork; larger squash may need a couple more minutes. Let it rest a minute before scooping out strands. If you prefer a deeper roasted flavor, roast the halves in a 400°F (200°C) oven for 30–45 minutes until tender and slightly caramelized.
Tips, variations and serving ideas
- Make the pesto ahead and refrigerate for up to three days or freeze in ice-cube trays for quick portions later. Thaw before using.
- Swap Parmigiano-Reggiano for Pecorino Romano if you prefer a sharper, saltier cheese—adjust the salt accordingly.
- Add a squeeze of lemon juice to the pesto for brightness, especially if tomatoes are less sweet.
- Stir in cooked chickpeas, white beans, or toasted walnuts for extra texture and plant-based protein.
- Leftover pesto-squash is delicious cold in a summer pasta salad or reheated gently on the stove.
Yield, time and nutrition
Yield: about 4 servings. Prep time roughly 10 minutes; cook time about 10 minutes using the microwave; total time about 20 minutes. Estimated nutrition per serving: ~165 calories, 7 g carbohydrates, 2.5 g protein, 15 g fat, 1.5 g fiber.
Other spaghetti squash ideas
- Spaghetti Squash with Bacon and Parmesan
- Spaghetti Squash Primavera
- One-Pot Spaghetti Squash and Meat Sauce (slow cooker or Instant Pot)
- Spaghetti Squash Enchilada Bowls
- Spaghetti Squash Sausage Lasagna Bowls
If you make this recipe, consider sharing how it turned out—what additions you tried or which method (microwave vs. oven) you prefer. Fresh basil and a simple homemade pesto make this spaghetti squash dish feel like summer on a plate, but it’s easy enough to enjoy any time of year.