In a large bowl, beat the butter until smooth.
Add the powdered sugar, cocoa powder, and optional pinch of salt, and beat them into the creamed butter.
Add the vanilla to the milk. Then gradually beat the milk-vanilla mixture into the buttercream.
Scrape down the bowl, then beat again until the color is a bit lightened and the buttercream is very smooth.
If it’s too stiff, beat in a little more milk. If it’s too thin, beat in a little more powdered sugar until you reach the consistency you want.
Your buttercream is now ready to use. Once it’s on a cake, it’s fine to keep it at cool room temperature for a few days.
Refrigerate the buttercream in an airtight container for up to 2 weeks. Let come to room temperature and beat thoroughly before frosting cakes or cupcakes.
You may also freeze the buttercream in an airtight container for up to 6 months.
