1. Beat the softened butter in a large mixing bowl on medium speed for about two minutes until creamy and pale.
2. Add cocoa and sugar, gradually reduce speed to low. Add the cocoa powder and powdered sugar, one cup at a time, mixing slowly so you don't get a cloud of sugar. Once combined, increase speed to medium and beat until fully incorporated.
3. Add coffee and vanilla. Mix in the brewed coffee and vanilla extract. The coffee enhances the chocolate flavor without making it taste coffee-forward, perfect for pairing with your cake.
4. Adjust consistency. Add heavy cream, 1 tablespoon at a time, until your frosting reaches the consistency you like.