Steam cauliflower until fork tender. Place in a high speed blender and blend until completely smooth. Set aside.
Place a large nonstick pan over medium heat. Add olive oil to a pan then add the yellow onion and cook for 5 minutes. Then add garlic cloves and cook for 2 more minutes. Lastly, add the chicken broth, nutritional yeast, lemon juice, and coconut aminos. Mix to combined,
Pour the blended cauliflower into the pan, then add salt, garlic powder, and black pepper. Let come to a low boil for 5 minutes to thicken.
Mix the alfredo with cooked noodles and top with fresh parsley!