In a stand mixer, using the paddle attachment, beat the softened butter for 1-3 minutes on high speed, or until the butter is creamy and slightly pale.

While the espresso shot is still hot, add the finely ground espresso beans and mix together.

In a small bowl, add the espresso mix, vanilla, and 1 1/2 cups (180g) of powdered sugar. Whisk everything together until a thick mixture forms.

Add the espresso mixture to the butter and mix together.

Add the kosher salt and the remaining powdered sugar, one cup at a time, until fully combined.

Adjustments: If the buttercream is too sweet you can add a pinch of kosher salt to reduce the sweetness. If the buttercream is too thin, you can add more powdered sugar, 1/4 cup at a time. If the buttercream is too thick, you can add heavy cream, one tablespoon at a time.

Frost your cake or cupcakes of choice and enjoy!