Make the dough:

1. Turn on your grain mill and process the wheat berries on the finest setting on your grain mill.
2. Use a fine mesh sieve (I use this inexpensive #60) to sift out the bran onto a piece of wax paper or parchment.
3. Weigh the sifted flour. You need 130 grams for this recipe.
4. Using a paddle attachment on a stand mixer, mix the powdered sugar, butter and egg yolk until just combined.
5. Add in the vanilla and the salt to the butter to combine. The mixture should be well-combined but not fluffy.
6. Pour in the flour, then pulse the mixer a few times before letting it run just long enough for the flour to disappear–about 10 seconds. Turn off the mixer, and use a baking spatula to squish in any flour that’s hanging out at the bottom of the bowl.

Rolling the cookies

1. Get 2 pieces of parchment out and have 2 sheet trays at hand.
2. Lightly flatten the dough ball with your hands into a flattish round.
3. Lightly sprinkle one of the sheets of parchment with flour, then sprinkle flour on the top of your dough flat.
4. Place the dough unfloured side down on top the floured parchment, then cover with the second piece of parchment.
5. Bring the edge of the parchment to the edge of the counter and hold it in place with your hip.
6. Roll the dough between the two sheets of parchment into a sheet about 1/8″ thick.
7. Slide the parchment onto a baking sheet and chill for 15 minutes in the fridge or 10 minutes in the freezer.
8. Preheat the oven to 350 degrees F (180 C).
9. After 15 minutes, peel off the top piece of parchment.
10. Use a 2″ round cutter to cut cookies. Place the top parchment on the second sheet tray, then place the cut cookies. They will spread a tiny bit, but you should be able to fit 20 on one sheet.
11. Bake for 5 minutes, then rotate the baking sheet 180 degrees.
12. Reroll any scraps into a second sheet of dough, then chill while the first batch of cookies is baking.
13. Bake for 5 more minutes until the edges are set and just beginning to take on color.
14. Let the cookies sit on the sheet tray until the baking sheet is cool.
15. Bake the second batch the same way as the first.
16. Store cookies in an airtight container for up to a week or freeze them for up to 3 months.