Recipe inspired by: Whole 30, A Family Feast, and Real Simple
Heat oven to 400 F.
Slice squash in half lengthwise and scoop out seeds. Drizzle inside with olive oil and season with salt. Place squash cut side down on baking sheet and roast until tender, 45-50 minutes. Use a fork to scrape out “spaghetti.”
In the meantime, heat a dry skillet over medium-high heat. When the pan is hot add the walnuts in a single layer and stir or shake frequently until lightly browned, about 2 minutes.
Combine the walnuts and garlic in a food processor and pulse a few times. Add the basil and spinach and pulse until coarsely chopped. Add the lemon juice. While mixing on low speed, add the olive oil in a slow stream until all the ingredients are fully blended. Add the salt and pepper and pulse a few more times.
Toss "spaghetti" with pesto and tomatoes. Any leftover pesto can store in the fridge and used within 2-3 days.