½cupheavy creamroom temperature (give or take a few tablespoons)
In a medium microwave-safe bowl, combine the chocolate and coconut oil. Melt in 30 second increments, stirring in between until smooth. Alternatively, you can melt the chocolate and coconut oil together in a heat-proof bowl set over a pan of barely simmering water. Set aside to cool to lukewarm.
In a large bowl, beat the butter and cream cheese together until smooth. Beat in the powdered sweetener and the cocoa powder until well combined.
Add the chocolate and vanilla extract and beat until smooth. The mixture will be very thick at this point.
Add the cream a few tablespoons at a time until a spreadable consistency is achieved. (How much cream you need depends on the other ingredients...certain brands of cream cheese and cocoa powder have more fillers and fiber, which thicken the frosting and require more cream).
This makes enough frosting for 12 cupcakes or a single layer cake. You may need to do 1.5 to 2x the recipe for larger cakes.