Cool 2 stainless steel or glass bowls in the freezer beforehand.
In the first bowl, pour half of the whipped cream. Add 15 ml of calorie-free sweetener and vanilla. Whip at medium speed until firm peaks form. Cover and refrigerate.
In a second bowl, mix 15 ml of calorie-free sweetener with cocoa powder. Add the whipped cream and whip at medium speed, scraping the sides with a spatula, until firm peaks form. Cover and refrigerate until assembly time.

Assembly:
Use transparent glasses or cups for assembly. Place a good spoonful of whipped cream with chocolate at the bottom. Arrange pieces of small fruits and cover with another spoonful of vanilla whipped cream. Alternate to fill the glass. Decorate with a mint leaf if desired, dark chocolate shavings, toasted coconut, or chopped nuts.