Deeply complex flavor from minimum ingredients is one way to describe Japanese cooking, and these cookies fit that bill. They're very tender and moderately sweet with a tiny touch of mushroom and a parade of indescribable but excellent tastes. You'll be amazed by how easy, and how rewarding, they are.
Making koji rice is an involved and finicky process, but pre-made koji can be found in Asian supermarkets. Commercial batches tend to be less sweet than the koji I've made at home. Taste what you obtain, and if not sweet, add 1/3 more sugar than the recipe specifies.
Yield: About a dozen, 2-ounce drop cookies. Cookies may also be cut from dough sheets.
Time to make: 20 minutes active. 18 minutes oven dwell
Tools needed: Spice or coffee grinder. 2 medium bowls. Hand mixer. cookie sheet with bakers parchment. Measuring cups and spoons or kitchen scale. Cooling rack. Optional: Rolling pin, plastic work surface, cookie cutters.
Ingredients
Note:
To make flour from Koji rice - place about 1/4 cup at a time into a spice or coffee grinder. Run the grinder 30 seconds, then stop and shake to redistribute contents. Grind and shake 3 or 4 more times until a fine flour results. Flour may be sifted and coarse parts re-ground, if desired.
Procedure:
1) Heat oven to 325 F. Position an oven rack in a middle slot. Line a baking sheet with a piece of bakers parchment. Grind the koji rice into flour - see note.
2) In a medium bowl, whisk together the koji rice flour, the baking powder, the xanthan gum, and the salt.
3) 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. If dough will not come together, add heavy cream with stirring, one Tablespoon at a time, until the dough comes together in a soft and pliable mass.
4) Remove dough in 2-Tablespoon scoops. Roll by hand into balls and place on parchment, spacing at least 3/4 inch apart. If balls crack or crumble, return to bowl and add more cream. 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.
5) Cut-out cookie option: chill dough in the refrigerator 1 hour. Dust a plastic work surface, rolling pin and cookie cutters with potato starch. Gently roll dough into a sheet that is 1/4 inch thick. Cut out cookies and transfer to the parchment-prepared baking sheet. Sprinkle with decorative sugar and gently press sugar into dough. Bake 12 - 15 minutes, or until edges are slightly browned. Allow cookies to cool for 10 minutes before carefully transferring to a cooling rack. Cookies are very delicate. They may be frosted if desired.
Cookies may be frozen for later consumption.