Step 1

Sift together the sweet rice flour, oat flour, chestnut flour, tapioca starch, xanthan gum, baking soda, ginger, cinnamon, allspice, cardamom, and salt in a medium bowl.

Step 2

In the bowl of a stand mixer fitted with the paddle attachment, or by hand, stir together the molasses, brown sugar, 1/3 cup of granulated sugar, butter, and bacon fat until completely combined.

Step 3

Add the egg and vanilla extract and beat until well combined.

Step 4

With the mixer on low speed, slowly add the dry ingredients, one cup at a time, mixing until completely combined. The dough will be rather soft.

Step 5

Form the dough into a flattened ball, wrap it in plastic, and refrigerate for at least 2 hours, but preferably overnight.

Step 6

When you're ready to bake, position a rack in the top third of the oven and preheat to 350°F. Line two large baking sheets with parchment paper.

Step 7

Prepare a small bowl of the remaining 1/3 cup of sugar.

Step 8

Scoop and roll 1½-inch balls of dough, roll each ball in sugar, and place 2-inches apart on the baking sheet. Refrigerate the first baking sheet for at least 10 minutes, while you roll the rest of the cookies.

Step 9

Bake the chilled baking sheet for 8-10 minutes until the cookies puff and the tops just begin to crack while the dough underneath looks under baked (err on the side of under baked or else your cookies will be more cakey than chewy). After 5 minutes, crack the oven open and sprinkle the cookies with flaky salt.

Step 10

While the first sheet is baking, chill the second baking sheet and repeat the baking with the second sheet.

Step 11

Cool the cookies for a couple of minutes on the baking sheet then transfer to a wire rack to cool completely.