Gosh, that is pretty! Do you do anything special to your "mash"?
Nothing special. I saute some onions and garlic until soft. Add chopped cauliflower, season with salt and pepper, saute until soft. Add milk, just about cover the cauliflower. Bring to a boil, then reduce heat , cover and simmer until very tender.
Fish out the cauliflower into a blender, add the milk a little at a time and puree until desired consistency.
Adjust seasoning