2 sticks unsalted butter, room temperature, sliced into chunks
¾ cup granulated sugar
zest of 1 blood orange (about 1½ teaspoons packed down)
1 egg, yolk and whites separated
1 teaspoon vanilla
confectioner's sugar for dusting
Instructions
In a food processor, grind ½ cup of almonds as small as possible (set aside the remaining almonds for toppings).
Combine ground almonds, flour, baking powder, and salt in a large bowl.
Using an electric mixer, beat together butter and sugar until fluffy, about 3 minutes. Add in zest, egg yolk, and vanilla. Continue to beat until fully integrated.
Add dry ingredients to mixer and beat on low speed until dough forms.
Using your hands, form the dough into two 1-inch thick logs. Wrap in plastic and put in freezer for about 45 minutes.
Preheat oven to 350 and line two baking sheets with parchment paper.
Slice each log into 18 evenly sized cookies and place on baking sheet. Dip each cookie into remaining egg white, and then sprinkle with remaining almonds.
Bake cookies until golden brown, about 15 minutes. Let cool for 5 minutes and dust with confectioner's sugar.
Recipe by Things I Made Today at https://www.thingsimadetoday.com/2013/02/24/almond-and-blood-orange-cookies/