Line 2 sheet pans with parchment paper and preheat the oven to 415°F.
In a large mixing bowl, toss together the onion, red bell pepper, orange bell pepper, zucchini, yellow squash, tomatoes, broccoli florets, and carrots with the olive oil, salt, and pepper. Make sure the veggies are well coated in olive oil and seasonings.
Scatter the veggies over the prepared baking sheets and roast for 20-25 minutes or until tender.
While the veggies are roasting, bring a large pot of water to a boil. Add the salt and then the pasta. Cook the pasta to the package’s instructions until al dente. Drain the pasta, reserving 1 cup of pasta water. Set aside.
While the pasta is cooking, heat the olive oil and vegan butter over medium heat in a large, heavy-bottomed pan. Once the butter has melted, add the garlic and saute until fragrant. Add the lemon juice, frozen peas, and red pepper flakes. Saute for 1 minute.
Stir the pasta into the sauce. Add the nutritional yeast and stir until it melts into the sauce. Add a little pasta water to help the process along if needed. Stir in the roasted veggies.
Serve warm garnished with chopped fresh parsley.
Notes
To store: Transfer leftover pasta primavera to an airtight container and refrigerate for up to 4 days. Reheat it in a skillet over medium-low heat with a splash of water or broth, or in the microwave.To freeze: Technically speaking, you can freeze this recipe, but do be aware that the vegetables may lose their texture when thawed and reheated and the pasta is likely to be a bit mushy. If you’re okay with this, store it in an airtight container for up to 2 months and thaw in the fridge before reheating.