Cream the butter and cocoa powder for 2-3 minutes, until the cocoa powder begins to lighten in color. Add in the powdered sugar, milk, vanilla extract, and salt, beating until light and fluffy, about 1 minute.
Place first cake on a cake stand, then top with generous amount of frosting. Layer second and third layers, frosting the same amount in between each. Frost edges of cake with remaining frosting. Top with flowers, sprinkles, or whatever your heart desires. Enjoy any day!
*TIP: We like to freeze or refrigerate our cakes before frosting. This make the frosting process much easier and sturdier and can help prevent getting crumbs in your buttercream!