Photo by Charles Luce
Provenance of Dish
Ever since I read how to grow koji - a dense mat of Aspergillus oryzae yeast - in René Redzepi’s and David Zilber’s book, The Noma Guide to Fermentation, I’ve been making, harvesting, and grinding flour from fungally-transformed - which is to say koji - rice. The cookie recipe below is my invention using this flour.
While koji cookies may take the concept of culinary mycophilia to an extreme, they’re a perfect example of fungal transformative power. The bland grittiness of white rice flour is a world away from koji flour, which is chewy, sweet, loaded with umami and vaguely yet compellingly mushroom-y.
Experienced bakers will realize the ingredient list is strangely limited. An absence of flavorings and eggs allows koji’s mysterious flavor bouquet to shine unimpeded, and its native sweetness drives down the usual sugar requirement.
Koji is tricky to cultivate, but many Asian markets carry it pre-made, as shown in the photo. The commercial varieties I’ve bought are much less sweet than what I’ve made following Redzepi’s and Zilber’s instructions, so if you use commercial you may need to adjust this recipe.
1 1/3 cup (200 grams) koji rice - rice that has been overgrown with Aspergillus oryzae. Note: Commercial "blocks" are usually 200 grams.
1 teaspoon xanthan gum
1 teaspoon baking powder
1/8 teaspoon salt
4 1/3 Tablespoons (66 grams) unsalted butter, softened slightly
6 Tablespoons (66 grams) coconut oil
3 Tablespoons (40 grams) granulated sugar
Heat oven to 325 F.
Position an oven rack in a middle slot.
Line a baking sheet with a piece of bakers parchment.
Place the koji rice into a spice or coffee grinder and grind to a fine powder, shaking the grinder occasionally to distribute the contents.
In a medium bowl, whisk together the koji rice flour, the baking powder, the xanthan gum, and the salt.
In a second medium bowl, cream the butter and coconut oil until light in color and forming soft ridges.
Add the sugar and cream again, until soft peaks form. Add the flour mixture and stir on a low setting until thoroughly blended. Using your hands, form dough into a compact mass.
Remove dough in 2-Tablespoon-size scoops.
Roll by hand into balls and place on parchment, spacing at least 3/4 inch apart. Use the bottom of a glass or plastic measuring cup to flatten balls to about 1/2 inch thick discs.
Bake for 18 minutes, or until lightly browned, turning baking tray once. Remove to a cooling rack. Allow cookies to cool slightly before removing from the cookie sheet and placing directly on the rack.
Cookies may be frozen for later consumption.