How to Make It
Heat oven to 350° F. Line baking sheet with parchment paper and set aside.
In the bowl of the stand mixer, add peanut butter and brown sugar. With the paddle attachment and on low/medium speed, mix the two together for 1 to 2 minutes. With the mixer still on, add the baking soda, egg, and vanilla extract.
Roll about ½ tablespoon of dough into a ball (do not chill dough). Place on the baking sheet. With a fork, press down slightly to make the traditional crisscross marks on top. Continue this process, leaving ½-inch in between each cookie.
Bake for 7 to 8 minutes. Remove and let cool. Once they’ve completely cooled, spoon about 1 teaspoon of jam or preserves on the flat side of a cookie, then sandwich with another–flat side to flat side. Continue this process until all cookie sandwiches are complete.