Cheesy Microwave Cauliflower

Okay, so not a very "original" name for this quick side dish, but it's one of those sides that everyone always seems to enjoy, so I thought I'd post it :) It is so easy to throw together and cooks in the microwave...BONUS! To be completely honest, I never exactly measure the ingredients, so I'm just going to give you the approximate measurements and you can play around with it to your liking.
(It tastes better than it probably looks!)

Cheesy Microwave Cauliflower

One large head of cauliflower
3/4-1 cup mayo (or Miracle Whip...I tend to prefer the sweetness of Miracle Whip)
3 Tablespoons of mustard (you can adjust the amount if you aren't much of a mustard fan or increase it if you are especially fond of mustard!)
5-6 slices American Cheese

Wash cauliflower, remove leaves and some of the bottom core, if it's especially bulky at the bottom. Place cauliflower in a microwave-safe dish (preferably with a lid, but you can always use wax paper, too!) and add approximately 1/2 cup of water. Combine mustard and mayo in a small bowl and spread generously over the cauliflower. Microwave, covered, for approximately 15 minutes or until desired tenderness is achieved. When cauliflower is done cooking, leave in microwave, remove cover, place American cheese slices all over to cover entire head of cauliflower and allow to sit in microwave for a few minutes until cheese melts.