These cupcakes have a triple dose of coffee flavor in the cake, frosting and the doughnut glaze!Please note the frosting uses salted butter, to add mild salty-sweet flavor to the buttercream. Espresso powder can be found in the coffee aisle at the grocery store, and sometimes in the baking aisle. I use DeLallo brand most often. However, Medaglia D’oro and other high quality freeze-dried instant coffee can be used in place of espresso powder. For example, Starbucks VIA instant coffee has bold coffee flavor, is micro-ground, and dissolves easily.