1 tablespoon very strong brewed coffee with extra to use 1 cup (8 ounces) unsalted butter, at room temperature 1 1/4 cups (10 ounces) confectioners' sugar, divided 1 teaspoon vanilla extract 1/4 teaspoon salt 2 cups (8 1/2 ounces) all-purpose flour 2 tablespoons coarsely ground coffee (i