From http://chocolatecoveredkatie.com/2012/01/16/chocolate-frosting-shots/

1 can full-fat coconut milk or coconut cream
1/4 cup plus 1 tbsp cocoa powder or cacao powder
1/2 tsp pure vanilla extract
sweetener of choice to taste (Use stevia or powdered sugar for thickest results.)

1 can full-fat coconut milk or coconut cream 1/4 cup plus 1 tbsp cocoa powder or cacao powder 1/2 tsp pure vanilla extract

Open your coconut milk, and if it's not already super-thick, leave the can (or transfer to a bowl) uncovered in the fridge overnight. Try not to shake the can too much before opening. It should get very, very thick. (If it doesn’t, you’ve gotten a bad can that won't work for the recipe. I recommend Thai Kitchen Organic. Hint: shake the can when you're at the store. If you can hear the liquidy contents swishing around, it's probably too thin to work for this recipe. Or if you want a no-fail option, buy coconut cream instead, at Trader Joes or an Asian market.) Once thick, transfer only the creamy part to a bowl, leaving the watery part out. Whip in your cocoa, vanilla, and sweetener with a fork, or even beaters if you want to be fancy. For the photos on this page, I didn't use beaters. But I did pipe the chocolate frosting shots out using an icing tip. Stored uncovered in the fridge, the mixture gets even thicker.