In a large mixing bowl, beat the softened cream cheese and butter together using an electric mixer on medium speed until smooth and creamy, about 2-3 minutes.
Gradually add the powdered sugar, mixing on low speed until combined.
Pour in the cooled espresso, vanilla extract, and salt. Beat on medium speed until the frosting is light and fluffy, about 2-3 minutes.
If the frosting is too thick, add a little more brewed espresso, one teaspoon at a time, until the desired consistency is reached.
Use immediately to frost your favorite cakes or cupcakes, or refrigerate for up to one week. If refrigerating, let it sit at room temperature for about 15 minutes before using to soften.