1. Preheat the oven to 425˚F (220˚C).
2. Peel and chop the sweet potato into ½-inch chunks. Slice the mushrooms. Toss the vegetables with olive oil, salt, and pepper, and spread in an even layer on a baking sheet.
3. Roast for 20-30 minutes, until golden-brown and tender.
4. Meanwhile, boil the pasta according to the package instructions.
5. Combine the pasta, roasted vegetables, and spinach, and season with olive oil, salt, pepper, and red pepper flakes.
6. Scoop half of the pasta salad into a bowl and store the other half in an airtight container for another day.