Adding almonds to these shortbread cookies gives them an unexpected but welcomed crunch.
Preheat oven to 325 degrees. In a medium bowl, whisk together flour, cornstarch, pepper, cardamom, and salt; set aside.
In the bowl of an electric mixer fitted with the paddle attachment, cream butter and one cup confectioners' sugar until light and fluffy. Add almond extract; beat to combine. With mixer on low speed, gradually add flour mixture until it comes together to form a dough, scraping down sides of bowl as needed.
Turn out dough onto a clean work surface. Pinch off tablespoons of dough; roll into 1 1/2-inch balls. Place on two baking sheets, two inches apart. Flatten slightly. Cover with plastic wrap, chill 30 minutes.
In a small bowl, lightly whisk egg white. Add blanched almonds, and toss to coat. Remove dough from refrigerator; press two almonds on top of each ball.
Bake until slightly golden, about 18 minutes. Remove from oven; immediately transfer cookies to a wire rack.
Place remaining 1 1/2 cups sugar in a medium bowl. Roll warm cookies in sugar, and return to baking sheets; let cool 15 minutes, then roll again in sugar.
Store in airtight containers at room temperature up to one week.