A light chocolate mousse with a truly secret ingredient, perfect for children (you will understand why later), super healthy, with a low glycemic index, and excellent in flavor. Virtually a low calorie dream!  
But what is the secret ingredient of this mousse? I state that I have tried it, and it is fantastic.
The cauliflower. You got it right: boiled cauliflower will allow you to have a light, frothy, creamy chocolate mouse, without feeling the taste or smell of cauliflower. The important thing is to consume it the same day. Here is the recipe!

LIGHT CHOCOLATE MOUSSE: THE SUPER RECIPE!
Ingredients for 4 people.
Calories per serving: about 200
(A serving is equivalent to a generous cup, attention, over 270 grams of product!)

4 cups of already boiled white cauliflower, or one kg raw  (to boil it, put it in water in pieces with cloves and half an apple cut into wedges: this will eliminate the bad smell from the vegetable: then drain it very very well)
75 grams of bitter cocoa
100 ml of Tibiona type coconut milk (please, not coconut-flavored drink!)
50 grams of honey and a sachet of stevia (if you want you can reduce the calories to stevia alone)
a teaspoon of espresso
a pinch of salt

Blend the cauliflower with the coconut milk and honey: add the cocoa a little at a time, until you get a thick and foamy cream.