1/2 cup peanut butter
1 cup light brown sugar
1 large egg
1 1/2 cups all-purpose flour
1 teaspoon baking soda
Pinch salt
Granulated sugar, for sprinkling
Preheat the oven to 350°F (180°C). In a large bowl with a stand mixer or an electric mixer on medium-high, beat the bacon fat, peanut butter, and sugar until it lightens in color and the texture becomes creamy, 2 to 3 minutes. Add the egg and keep beating until completely incorporated. In a separate bowl, combine the flour, baking soda, and salt. Slowly add the flour to the peanut butter mixture, beating until all the ingredients are combined well. Roll the dough into balls about 1 inch (2 1/2 centimeters) in diameter. Place the cookie dough about 1 inch (2 1/2 centimeters) apart on a baking sheet and gently press the top of each cookie dough ball with a fork dipped in granulated sugar to make criss crosses. Bake for 9 to 10 minutes, until barely browned around the edges. The cookies may look a little underdone and may appear slightly puffed and that's okay. Let the cookies cool on the baking sheet for at least 5 minutes and then gently transfer the tender, delicate cookies to a wire rack to cool completely.