Weigh 170 grams of soft white wheat berries and mill them into fine flour. In a small bowl, whisk together the freshly milled flour, cocoa powder, baking powder, and salt. Set aside.
In a large mixing bowl, use a hand mixer or stand mixer fitted with the paddle attachment to combine the granulated sugar, brown sugar, and softened butter. Mix on medium speed until well combined.
Add the eggs one at a time, mixing after each addition, then mix in the vanilla extract.
Gradually add the dry ingredients to the wet ingredients and mix on low speed just until combined. The dough will be thick and sticky, which is completely normal!
Cover the bowl and refrigerate the dough for at least 4 hours or overnight. This helps firm up the dough so it's easier to handle and gives the freshly milled flour time to absorb moisture.
Once the dough has chilled, preheat your oven to 375°F and line a baking sheet with parchment paper. Using a 1-inch cookie scoop or tablespoon, scoop out enough dough for one batch and roll each portion between your hands into a nice, round ball.
Roll each dough ball generously in powdered sugar until completely coated, then arrange them a few inches apart on the prepared baking sheet. Keep the remaining dough in the refrigerator between batches.
Bake for 8-10 minutes, or until the edges are firm and the centers are puffed but still look slightly wet. My bake perfectly at 9 minutes. Let the cookies cool on the baking sheet for a few minutes before transferring them to a wire rack. Repeat with the remaining chilled dough, making sure to use a cool baking sheet for each batch.