Add cauliflower to a large pot and add water to cover. Bring to a boil over high heat and cook until the cauliflower tender, about 10 minutes.
Once tender, drain water and puree the cauliflower with an immersion blender until smooth. Add non-dairy milk if needed to achieve desired consistency. Set puree aside while prepping the rest of the sauce.
Put onion in a large saucepan and saute over medium heat until translucent. Add 1-2 tablespoons of water as needed to keep onions from sticking to the pan.
Add garlic, thyme and basil and cook for another minute or two.
Add 1/4 cup nutritional yeast, nutmeg, salt and pepper to the onions and cook for 3-5 minutes.
Add the onion and garlic mixture to the cauliflower puree along with Braggs Liquid Aminos and lemon juice and blend until smooth. Add the remaining nutritional yeast, adding 1/4 cup at a time until desired taste and consistency is reached. Add more non-dairy milk or water if needed to achieve desired consistency.