Very, very lightly adapted from Mindy Segal's wonderful "Cookie Love." Note that it makes 42 cookies. (But I've halved it successfully, fudging the half-egg and all. I've also used all kosher instead of the half sea salt flakes Segal recommends.) —Nicholas Day
plus 2 tablespoons old-fashioned oats
(8 ounces) unsalted butter, at room temperature
Heat the oven to 350° F and line a couple of half sheet pans with parchment paper.
On another sheet pan, spread the oats and toast lightly, for approximately 5 minutes. Once they've cooled, grind 2 tablespoons of the oats into a fine powder.
In a stand mixer, use the paddle attachment to mix the butter very briefly, 5 to 10 seconds, on medium speed. Add the sugars and beat until the butter mixture is pale in color, about 4 minutes. Scrape the sides and bottom of the bowl.
In a small bowl, crack the egg and add the vanilla. In a different and larger bowl, whisk together the powdered and whole oats, flours, baking soda, and salts. Add the butterscotch chips and stir lightly.
On medium speed, add the egg and vanilla to the butter mixture and beat very briefly, about 5 seconds. Scrape the sides and bottom of the bowl. Mix again on medium speed for another 20 seconds, until well-combined. Then add the dry ingredients all at once and mix on low for approximately 30 seconds; the batter will come together in a shaggy sort of way. Do not over-mix. With a bowl scraper, mix the rest of the dough together by hand.
Scoop out the dough with an ice cream scoop (technically, a 3/4-ounce or 1 and 1/2 tablespoon scoop) and place on the prepared cookie sheets, with a good amount of space between each. Each half-sheet pan should take no more than 8 cookies. (They'll spread.) Bake for 8 minutes. Then rotate the pan, and in the process, tap it against the counter or the oven to deflate the cookies. Bake for another 4 to 6 minutes, or until the edges are a deep golden color and the cookies are beginning to crisp and brown. Let the cookies cool on the pan. Repeat with the remaining dough. Store in an airtight container for up to 3 days.