Combine the cocoa powder and dark rum and leave to infuse overnight.

Once infused, strain the cocoa powder mixture through a cheesecloth. Combine the simple syrup, white rum, and coconut rum with ice and shake until well chilled. Add the cream and give it a couple more shakes. Pour into a glass with ice.

Carefully pour the cocoa infused rum over the top of the drink, pouring it onto the back of a spoon, so it will float on the top, and serve.