1 ¼cupsall-purpose flour or a 1:1 gluten-free flour such as Measure for Measure(160 grams)
½teaspoonsalt plus a pinch but omit pinch if salted
¼teaspoonbaking powder
1stickunsalted butter, softened, but I think salted would be good too(120 grams)
½teaspoonvanilla
1largeegg yolk
Instructions
Preheat oven to 325°F. Line a 9 inch square pan with foil and spray lightly with a little bit of cookie spray or grease with a little extra butter. Make sure you put enough foil over the pan so that you can grasp it and lift it.
Pulse toasted pecans with 2 tablespoons of the confectioners' sugar in a food processor until finely ground.
Whisk together flour, salt, and baking powder in a bowl.
Beat the softend stick of butter (114 grams), with the remaining ⅔ cup confectioners' sugar, and vanilla in a bowl with an electric mixer. Add the egg yolk and beat until blended. Add flour and ground-pecan mixture and mix at low speed until just combined.
Press the dough into the lined pan, making the top as flat and as even as possible. I found it easier to empty the dough onto a piece of parchment paper, press it into a large square and just transfer it to the pan.
Bake for 25 minutes at 325 degrees F. Let cool for 5 minutes and reduce heat to 300 degrees F.
Carefully lift foil from the pan and place the square on a flat surface. The square will not be completely cooked at this point. With a chef's knife, score into sticks.
Return the scored shortbread to the oven and bake at 300 for another 25 minutes. Let cool completely, then separate the shortbread pieces. Store in a tin.