I loooooove mashed cauliflower. Like really love it, haha. There's a a small family of restaurants in the DC area (where my parents live) that serve mashed cauliflower as a side, and I got hooked.
I've found that the texture is better if I boil them till soft but not mushy, and then put them in the oven for a bit to dry out. Lets me add some heavy whipping cream or butter
Btw--purple would be amazing. I love a colorful plate!