In the bowl of a stand mixer fitted with the paddle attachment, combine the Cookie Jar Blend, sugars, salt, and baking soda and beat them briefly to combine. With the mixer still running, add the butter and beat it on the lowest speed for 5 minutes, until the mixture resembles damp cornmeal. Add the eggs, egg yolk, and vanilla and beat the mixture on high until the dough coats the sides of the bowl. Add the peanut butter and mix just to combine it.
Transfer the dough to a glass bowl, cover it, and refrigerate it for at least 24 hours and up to 48 hours for the best results. Preheat the oven to 350 degrees F (175 degrees C). Line two baking sheets with parchment paper or Silpat mats.
Spoon out a heaping tablespoon-size dollop of the dough (45 g) and roll it between your hands to form a ball. Pour 1/2 cup (100 g) granulated sugar on a plate and shake to level it. Roll the balls in the sugar and set them on the lined baking sheets. Stagger the cookie portions, leaving 2 inches (5 cm) between each. Press a peanut half into the top of each ball of dough.
Bake the cookies for 8 to 10 minutes, until they are golden. Let cool on the pan for 10 minutes, then transfer to wire racks to cool completely. These cookies keep beautifully in an airtight container at room temperature for up to 3 days. The dough can be frozen, double-wrapped, for up to 1 month.
Variation: Nutter Butters Prepare the dough as directed above but reduce the peanut butter to 1/2 cup (120 ml). Roll out the chilled dough to 1/8 inch (3 mm) thick and cut it into twenty-four 1-by-2-inch (2.5-by-5-cm) rectangles. Set the rectangles on parchment paper- or Silpat-lined baking sheets and press them flat with the tines of a fork. Squeeze the center of each rectangle, to give it a peanut-shell shape, and bake as directed above. Meanwhile, in a bowl, beat together 1 cup (240 ml) creamy or crunchy peanut butter, 2 cups (256 g) confectioners' sugar, 1 1/2 tablespoons milk, and 1/2 teaspoon pure vanilla extract. After the cookies have cooled, smear a little filling onto the backs (the side without fork marks) of half of the cookies. Make a sandwich by topping with a second cookie, back-side down. The cookies will keep in an airtight container for up to a week. The dough can be frozen, double-wrapped, for up to 1 month.
"The Everyday Art of Gluten-Free" by Karen Morgan. Copyright Stewart, Tabori & Chang 2014. Provided courtesy of Karen Morgan. All rights reserved.