Sainsburys do a tin of Cocoa Powder (with NO added sugar). 70p a tin and only 10.5g carbs in the whole tin.

I had a few strawberries, cream and a teaspoon of Cocoa. I intended to add some sweetener in but after tasting it, I didn't need to - strawberries were really ripe and sweet enough.

Boy ! did I enjoy that treat!
Take care