1. Fill a large pot with water. Season with salt and bring the water to a boil. Cook noodles al dente according to the directions on the package.

Make creamy cauliflower sauce

1. Fill a large pot with water and bring it to a boil.
2. Meanwhile, chop the cauliflower into quarters. Chop off the florets and cut the stems into approximately 1″ pieces so that the cauliflower cooks uniformly.
3. Place chopped cauliflower into a steaming basket and steam for 5-10 minutes, until the stems can be easily poked through with a fork.
4. Remove cauliflower from the basket, and place it in a blender or food processor. Puree the cauliflower until it is smooth, adding water only if necessary.

Make the Primavera

1. Meanwhile, melt butter in a large skillet. Add chopped garlic and onion and cook on low until garlic is light brown and onions are slightly translucent.
2. Add vegetables including broccoli stems (if using), except florets, and cook until just barely tender.
3. Mix in 1 cup of creamy cauliflower sauce, and shredded cheese and stir until cheese melts. Add water from the noodles, 1/4 cup at a time, as needed to thin the sauce. Keep the sauce on low until the noodles are done.
4. When the noodles are done, combine them with the sauce, fresh basil, and florets in the skillet. Toss to coat the pasta well. Season with salt and pepper, and serve hot with freshly shredded Parmesan cheese.