Kim Boyce is a former pastry chef at Spago and Campanile in Los Angeles. Her new book is Good to the Grain: Baking with Whole Grain Flours.
Butter for the baking sheets
1 3/4 cups barley flour
1/2 cup coconut flour
3/4 tsp kosher salt
1/2 tsp baking soda
1/2 tsp baking powder
1/2 cup sugar
1/2 cup dark brown sugar
1 1/4 cups light coconut milk
2 tsp pure vanilla extract
6 oz unsalted butter, at room temperature
2 1/2 cups shredded unsweetened coconut
1. Position two racks in the upper and lower thirds of the oven and preheat to 350 degrees. Rub two baking sheets lightly with butter.
2. Sift the dry ingredients into a large bowl, pouring back into the bowl any grain or other ingredients that may remain in the sifter, and set aside.
3. Crack the eggs into the bowl of a standing mixer fitted with a whisk. Whisk the eggs on low speed to break them up. Add the sugars, increase the speed to high, and mix until the color of milky coffee, about 3 minutes.
4. Measure out the coconut milk and vanilla and set aside.
5. Add the sifted dry ingredients to the egg mixture. Mix on low speed until combined. Add the butter and mix. Add the coconut milk and vanilla and mix until combined. Add 1 cup of shredded coconut and use a spatula to mix it in by hand. Make sure to scrape down to the bottom of the bowl to mix in any ingredient that may have been left behind.
6. Measure the remaining 1 1/2 cups of coconut into a shallow bowl. Scoop balls of dough about 3 tablespoons in size and dip the rounded side into the coconut. Gently left them out of the coconut and place them on the prepared baking sheets, coconut side up, leaving about 2 inches between them.
7. Bake for 16 to 20 minutes, rotating the pan halfway through, until the coconut crust is lightly toasted and the bottoms of the cookies are evenly brown. Use a spatula to transfer the cookies to a baking rack and bake the next round. These cookies are best eaten warm from the oven or later that same day. They'll keep in an airtight container for up to 3 days.