The best thing about this chocolate is that you can stash it in the freezer (out of sight) and then grab a piece when you feel the need (and eat it without having to wait for it to defrost). You could store it in the fridge, but the frozen berries will go soft and a bit liquid-y and it won't keep as long.
The recipe below is very rough. I haven't given specific quantities, so you can make as much or as little as you like (handy if you just want to make a single serve to satisfy a craving). It's so simple and easily adapted. Use your preferred natural sweetener and adjust the amount of cacao to suit your taste. I like to make it quite dark. You can also use different berries; frozen blueberries, blackberries or strawberries would also be nice.