Melt the chopped chocolate (or chocolate chips) in a microwave or a double boiler and set aside to come to room temperature while you mix the rest of the ingredients.
Place the butter and cream cheese in a medium mixing bowl and beat on medium high speed (with an electric mixer) until it is smooth and creamy. About 2 to 3 minutes.
Add the powdered sugar, cocoa powder, vanilla and salt. Stir them in a bit by hand then use the electric mixer to whip it up until it is smooth and creamy. Start on low speed so the dry ingredients don’t fly out of the bowl, then slowly increase the speed. Stop the mixer intermittently to scrape down the sides of the bowl.
Pour the melted chocolate into the mixing bowl and beat until it is all blended in and smooth. If the frosting is too stiff, add some cream or milk, 1 to 2 teaspoons at a time until you get your preferred consistency.
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Notes
Use room temperature ingredients: The butter and cream cheese should be soft to the touch. If they’re still cold, the frosting can turn lumpy, and the melted chocolate may clump instead of blending smoothly.Cream it first: Beating the butter and cream cheese together before adding the other ingredients helps create a smooth, fluffy frosting.Sift for smoothness: For the best texture, sift the powdered sugar to remove any lumps before mixing it in.Cool the chocolate: Make sure the melted chocolate has cooled to room temperature before adding it. If it’s too warm, it can melt the frosting and ruin the consistency.Worried about dark chocolate? Even if you're not a dark chocolate fan, this frosting mellows out thanks to the other ingredients, it ends up tasting more like smooth milk chocolate.Storage tips: Store in an airtight container for up to 5 days in the fridge or freeze for up to 6 months. Bring to room temperature and re-whip before using.Adjust the consistency: If the frosting is too thick, add a little cream or milk, about 1 to 2 teaspoons at a time, until it’s just right.Yield:This recipe makes enough frosting to cover 12 to 24 cupcakes, a two layer 8-inch cake, or a 9 x 13 inch sheet cake. For adding decorative swirls or other embellishments, consider making an additional batch of frosting.