In a large mixing bowl, combine the butter and granulated sugar until light and fluffy. Mix in the almond extract and egg yolk until fully incorporated. Gradually add the all-purpose flour, baking powder, and green food coloring until a soft dough forms.

Wrap the dough in plastic wrap and refrigerate for at least 30 minutes.

Remove the dough from the fridge and divide it into small portions. Roll each piece into finger shapes and press a blanched almond at the tip of each cookie.

Arrange the cookies on a baking sheet lined with parchment paper and bake at 350°F for 15 to 20 minutes, until pale but firm.

Let the cookies cool completely, then decorate with jam or melted candy melts for a bloody appearance.