Preheat oven to 375°F (190°C). Line a baking sheet with parchment paper.
In a large bowl, cream together the peanut butter, butter, and brown sugar until light and fluffy. Stir in the vanilla.
In a separate bowl, whisk together the flour, baking soda, and salt. Gradually add the dry ingredients to the peanut butter mixture and mix until combined.
Roll the dough into 1-inch (2.5 cm) balls and roll in the granulated sugar. Place on the prepared baking sheet and flatten slightly with a fork.
Bake for 8 minutes. Remove from the oven and let cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.
Once cooled, spread a generous amount of peanut butter between two cookies to make a sandwich.
Interesting Facts
Peanut butter was invented in the late 1800s by a Canadian doctor.
Peanut butter sandwich cookies were first popularized in the 1950s.
Peanut butter is a good source of protein and healthy fats.