Preheat your oven to 450°F (230°C) and line a baking sheet with parchment paper. Spread the frozen diced butternut squash, fresh chopped tomatoes, and sliced yellow onion evenly on the sheet. Drizzle with olive oil and season with salt, ground black pepper, and dried thyme. Toss everything together so the vegetables are evenly coated, then roast for 20 minutes until golden and cooked through. I always make sure the veggies are in a single layer to ensure even roasting.

While the vegetables are roasting, cook the pasta according to the package instructions in a large pot of boiling salted water. Just before draining the pasta, reserve 1/3 cup of the pasta cooking water and set it aside. Then, drain the pasta and keep it warm.

Once the vegetables are finished roasting, transfer them directly (while still hot) into a blender. Add the reserved pasta cooking water and blend everything until you have a smooth, creamy sauce. If the sauce seems too thick, you can add a splash more pasta water to loosen it up. I like to blend for a full minute to get the sauce extra silky.

Pour the blended sauce over the cooked pasta and toss everything together in the pot until the pasta is thoroughly coated with the sauce. Serve hot. For a richer flavor, I sometimes add a little grated parmesan or a sprinkling of plant-based parmesan right before serving.