6 tablespoons (84 g) unsalted butter, chopped
3 ounces semi-sweet chocolate, chopped
1 cup + 2 tablespoons (158 g) all purpose gluten free flour (I used Better Batter)
1/2 teaspoon xanthan gum (omit if your blend already contains it)
1/4 cup (20 g) unsweetened cocoa powder (natural or Dutch-processed)
1/2 teaspoon baking soda
1/4 teaspoon kosher salt
1/4 cup (50 g) granulated sugar
1/4 cup (55 g) packed light brown sugar
1 egg (50 g, weighed out of shell) + 1 egg yolk (25 g) at room temperature, beaten
1 teaspoon pure vanilla extract
Coarse sugar or nonpareils, for rolling (optional)
18 Hershey’s milk chocolate kisses, unwrapped
For the peanut butter version
Add 1/4 cup (64 g) peanut butter
Use 4 tablespoons (56 g) unsalted butter (not 6)
Use 2 ounces chocolate, chopped (not 3)
Use only 1 cup (140 g) all purpose gluten free flour (not 1 cup + 2 tablespoons)
Preheat your oven to 375°F. Line rimmed baking sheets with unbleached parchment and set them aside. In a small, heat-safe bowl, place the butter and chopped chocolate, and heat either over a double boiler or in the microwave in 30-second bursts until melted and smooth. Set the mixture aside to cool briefly. For the peanut butter variation, melt the peanut butter, 4 tablespoons of butter, and 2 ounces of chocolate in this way.
In a large bowl, place the flour blend (2 tablespoons less if making the peanut butter version), xanthan gum, cocoa powder, baking soda, salt, and granulated sugar, and whisk to combine well. Add the brown sugar, and mix to combine, working out any lumps in the brown sugar. Create a well in the center of the dry ingredients, and add the butter and chocolate mixture, egg and egg yolk, and vanilla, and mix to combine. The dough will come together and be thick but soft and shiny.
Divide the dough into 18 balls of approximately equal size (each weighing about 1 ounce). Between the palms of both of your hands, roll each piece of dough into a round, then roll it in the (optional) coarse sugar or nonpareils, pressing gently on all sides to make sure that the sugar adheres in a single layer to the cookie dough. Place the pieces of dough about 1 1/2-inches apart on the prepared baking sheets (they’ll spread a bit during baking). Place in the center of the preheated oven and bake for 10 minutes, or until the balls of dough have flattened into thick disks and the cookies have begun to take on a slightly crackled appearance.
Remove the baking sheet from the oven and immediately press one unwrapped chocolate kiss in the center of each just-baked cookie, as much as you can without cracking the cookie. Once the kiss has begun to melt a bit on the bottom, press down a bit on top to about halfway to the center of the cookie. Allow to cool on the baking sheet until firm (about 10 minutes) before transferring to a wire rack to cool completely. The chocolate kisses will firm up again as the cookies cool.