Coconut water is a popular drink in the kind of countries where coconuts grow easily. In the UK, it's gaining some traction as a health drink on account of its low calorie content and natural mineral content, which is the sort of thinking that leads me to wonder how you could possibly improve it. Let's add some rum, shall we?
While we're at it, we might as well pump the whole thing full of sugar and throw in a touch of bitters so that the whole thing satisfies the old "spirit-sugar-bitters-water" cocktail definition.
150ml coconut water
50g caster sugar
Gradually add sugar while stirring constantly until all the sugar is dissolved.
50ml 10 Cane Rum
20ml homemade coconut syrup
2 dashes Fee Brothers Aztec Chocolate Bitters
Stir all ingredients with ice and strain into an ice-filled rocks/old-fashioned glass. Garnish with a thin slice from a Bounty chocolate bar.