Coffee Sugar Cookie – 1 cup (226 g) unsalted butter – 1 tablespoon instant powder espresso – 2½ cups (300 g) all purpose flour – 2 teaspoons cornstarch – 1 teaspoon baking powder – ¼ teaspoon baking soda – 1½ cups (300 g) granulated sugar – 1 large egg (US), room temperature – 1 teaspoon (5 ml) vanilla extract Espresso Mascarpone Frosting – 8 oz. mascarpone cheese, cold – 1½ cups (180 g) powdered sugar – 2 teaspoons instant powder espresso – 1 teaspoon (5 ml) vanilla extract – 1 cup (237 ml) cold heavy whipping cream – 2 tablespoons (10 g) cocoa powder for dusting