Preheat the oven to 375 degrees. Line a cookie sheet with parchment paper. Spray the parchment with cooking spray and set aside.

In a large bowl whisk together the flour, baking soda and salt until thoroughly combined. Set aside. NOTE: We strongly recommend you weigh your einkorn flour, if possible, for better accuracy. If you don’t have a scale, fluff the flour with a fork before you measure it in a cup.

Melt the butter in a small sauté pan. Continue to cook until butter is brown and smells toasty. It will make bubbling noises until all the water has evaporated. Transfer to a heatproof bowl, scraping all the dark brown bits into the bowl (this contains the added flavor you just created). Refrigerate until butter is 80 degrees or less.

In the bowl of a stand mixer fitted with the paddle attachment, cream together the browned butter, both sugars, vanilla, egg and egg yolk for 2 minutes. Add the flour mixture and mix on low until just combined. Add the semisweet chocolate chips, mix until combined and place in the refrigerator for 30 minutes.

Using a 2 oz ice cream scoop, scoop cookie dough onto prepared baking sheet. Be sure to only use cool baking sheets. Repeat until all dough is used.

Bake for 9–10 minutes or until bottoms begin to brown. Remove from oven and pull parchment paper onto a cooling rack. While still warm, sprinkle with kosher salt if desired.