2 ounces dark chocolate or bittersweet baking chocolate (i i prefer bars or baking chocolate to chocolate chips)1/4 cup unsalted butter (1/2 of 1 stick)1/2 cup confectioners’ sugar1 large egg + 1 egg yolk (discard white or save for another use)3 tablespoons all-purpose flour1 teaspoon instant espresso coffee granu