01 - Preheat oven to 325°F. Line two baking sheets with parchment paper.
02 - Whisk together all-purpose flour, almond flour, baking powder, and salt in a medium bowl until thoroughly blended.
03 - Beat softened butter and granulated sugar in a large bowl until light and fluffy, approximately 2-3 minutes.
04 - Incorporate egg, almond extract, and vanilla extract into the butter mixture. Beat until fully combined and smooth.
05 - Gradually blend dry ingredients into wet mixture, mixing just until a soft dough forms. Avoid overmixing.
06 - Scoop tablespoon-sized portions of dough and roll into balls. Arrange 2 inches apart on prepared baking sheets.
07 - Flatten each dough ball slightly and press one blanched almond into the center of each cookie.
08 - Whisk reserved half egg yolk with 1 tablespoon milk. Lightly brush tops of cookies with egg wash mixture.
09 - Bake for 16-18 minutes until edges are lightly golden and cookies are set.
10 - Let cookies rest on baking sheets for 5 minutes, then transfer to wire rack to cool completely.