Bring a large pot of salted water to boil. Add the cauliflower and boil for 10 minutes until soft and tender.
While boiling cauliflower, heat the butter in a small skillet over medium heat. Add the garlic and saute for 2 minutes or until soft. Set aside.
When cauliflower is ready remove from heat and drain. Use a dish towel or cheesecloth to squeeze as much moisture out of it as possible.
In a food processor, add the cauliflower, garlic with butter, milk, Parmesan cheese, salt and black pepper and puree until smooth. Serve hot and sprinkle some rosemary or parsley on top.
Notes
If you can't get fresh cauliflower, frozen cauliflower will work fine. Just cook according to package instructions before adding to food processor.
Do not skip squeezing excess liquid out of cauliflower or it will be more soupy than you want.
Use freshly grated Parmesan to finish the sauce. Never buy pre-shredded Parmesan cheese as it contains wood pulp. Blocks of Parmesan cheese are also cheaper.
Be generous with salt and pepper to enhance the flavor. Taste and adjust the seasoning as needed. Don't be afraid to experiment with additional herbs, spices, or seasonings to personalize the taste.