Cut the cauliflower head into bite-sized florets. If using cashews for extra creaminess, place them in a small bowl and cover with hot water; let soak for at least 15 minutes, then drain.

Fill a large pot with about an inch of water, insert a steamer basket, and bring to a boil. Add the cauliflower florets, cover, and steam for 10-15 minutes, or until they are very tender and easily pierced with a fork. You want them soft enough to blend into a smooth sauce.

While the cauliflower steams, bring a separate large pot of salted water to a rolling boil. Add the pasta and cook according to package directions until al dente. Reserve about 1/2 cup of the pasta cooking water before draining the pasta.

Carefully transfer the steamed cauliflower to a high-speed blender (or food processor). Add the peeled garlic cloves, vegetable broth, drained cashews (if using), nutritional yeast, lemon juice, salt, and black pepper.

Blend on high until the sauce is completely smooth and creamy. If the sauce is too thick, add a splash of the reserved pasta cooking water or extra vegetable broth until it reaches your desired consistency. Taste and adjust seasonings as needed.

In the large skillet or Dutch oven (the same one you used for pasta, if large enough), combine the drained pasta with the creamy cauliflower alfredo sauce. Toss well to coat all the pasta evenly.

Heat gently over low heat for 1-2 minutes, stirring, until the pasta is warmed through with the sauce. If the sauce thickens too much, add a tablespoon or two of reserved pasta water to loosen it.

Serve immediately, garnished with fresh chopped parsley, red pepper flakes, and a sprinkle of vegan or regular Parmesan cheese, if desired. Enjoy your Creamy Cauliflower Alfredo Pasta!