PB & J Thumbprint Cookies

1. Preheat the oven to 350ºF.
2. Have a cookie sheet ready. Greasing it isn’t necessary for these cookies.
3. In a small bowl, whisk together the flour, baking soda and salt. Set aside.
4. In a shallow bowl or plate, pour half of the sugar for rolling the cookies in later.
5. In a medium bowl, whisk together the peanut butter, butter, remaining sugar, egg yolk, and vanilla. Whisk it until very well incorporated, then dump in the flour mixture and stir until combined.
6. Using a tablespoon, scoop dough balls and warm them in your hands as you roll into a ball. Roll in the reserved sugar, then place on the cookie sheet, evenly spaced.
7. Bake for 5 minutes, then use the handle of a small wooden spoon (or something similar) to make an indention about 1/2″ deep in each dough ball. Return to the oven for another 4-5 minutes, until the bottoms of the cookies start to slightly brown. Let cool completely.
8. Before serving, scoop 1/2 teaspoon of jam into each indention. In my opinion, these cookies are better the next day because the peanut butter flavor really shines through.