Break the cauliflower down into small pieces, using a knife if necessary. The smaller the pieces, the better (see photo below). Place the pieces in a medium-sized pot, and fill with water until the cauliflower is just covered. Don’t add too much, because you will not drain it at the end. Give the cauliflower a little stir, and any small pieces of leaf should float to the top. Take these out because they can be very bitter in taste.
Turn the flame on medium-high, cover the pot, and cook for approximately 10-12 minutes. Unlike when you make a broccoli and leave a bit of bite to it, you’ll want to cook this cauliflower entirely until it is soft all the way through. This will make a big difference in the blending process.
In a small sauté pan, sauté the garlic in the olive oil until softened. Don’t burn it or let it get bitter, it will affect the final taste of the sauce. Once softened, set aside.
When the cauliflower is softened, place it into the blender with all other ingredients; garlic, oil, and if you want, the Greek yogurt, and blend well. Add small amounts of the cauliflower water and blend again until you’ve got a thickness and consistency you are happy with. Puree the sauce until it is totally soft and creamy. If you’ve cooked the cauliflower thoroughly, it will get to that point.
Season thoroughly with salt and pepper (it will need it), and add the cheese on top if you want it. Note: This sauce freezes well. Enjoy!