Roast the Vegetables – Preheat oven to 400°F (200°C). Toss sweet potato, cauliflower, onion, and red bell pepper with oil and season with salt. Spread on a baking sheet and roast for 30-35 minutes, until softened.
Cook the Pasta – While the veggies roast, cook pasta according to package directions. Save 1 cup of pasta cooking water before draining.
Blend the Sauce – Once the vegetables are done, transfer them to a blender. Add Dijon mustard, garlic powder, cornstarch, milk, and shredded cheese. Blend until smooth.
Heat the Sauce – Pour the sauce into the pot used for cooking pasta. Heat over medium-low, stirring until warmed through.
Combine – Add the cooked pasta to the sauce and toss to coat. Use the reserved pasta water, a little at a time, to thin the sauce to your desired consistency. Season with additional salt and black pepper to taste. Enjoy warm!
