walnut shortbread

Preheat oven to 350°F.

Spread the walnuts in a single layer on a baking sheet and toast them in the oven for approximately 10 minutes, turning them every few minutes or so to cook evenly. They'll start to smell fragrant when they're ready. Do this ahead of time so they have time to cool.

Put the cooled nuts in the bowl of a food processor with a couple spoonfuls of the flour and process in about 5-second pulses until finely ground (the addition of flour here will help prevent the nuts from turning into nut butter). Combine the ground nuts, flour, and salt in a small bowl and whisk together. Set aside.

In the bowl of a stand mixer fitted with the paddle attachment, beat the butter and sugar together on medium speed until light and fluffy, about 3 or 4 minutes. Scrape down the sides of the bowl, then add the egg yolk and continue mixing until combined. Turn the mixer down to low and add the dry ingredients, mixing until just combined.

If the dough is too soft, it can be wrapped in plastic and refrigerated for about 30 minutes before continuing. Otherwise, on a lightly floured surface, a silpat sheet, or a sheet of wax or parchment paper (whatever your preference), roll the dough out to 1/4? thickness (or 1/2" if you want to try the original recipe recommendation – maybe it'll work better for you). Using a ruler as a guide, square off the edges and cut the dough into 1" squares with a sharp knife or a pizza cutter.

Transfer the squares to your baking sheet, about 2" apart, and sprinkle lightly with the coarse salt. Bake for about 10-12 minutes, until lightly golden brown, rotating the baking sheet halfway through. Allow to cool on a wire rack for a few minutes before removing the cookies from the pan and allowing them to cool completely.