1/2 cup (1 stick) unsalted butter, room temperature
1/2 cup peanut butter
1/2 cup granulated sugar
1/2 cup packed brown sugar
1/2 teaspoon vanilla
1 and 1/2 cups all-purpose flour
1 teaspoon cornstarch
1/2 teaspoon baking powder
1/2 teaspoon baking soda
granulated sugar (for rolling)
coarse sea salt (for sprinkling)
1 cup nutella
In the bowl of an electric mixer, beat butter and peanut butter until well combined. Add sugar and brown sugar and beat until light and fluffy. Mix in egg and vanilla. Add in flour, cornstarch, baking powder, and baking soda and slowly stir to combine. Scrape down sides of bowl and cover with plastic wrap. Refrigerate for 1-2 hours.
Preheat oven to 375 degrees. Line cookie sheets with parchment paper. Roll dough into tablespoon-sized balls, then roll in granulated sugar to coat. Place on backing sheet and press down slightly with a fork. Sprinkle with sea salt. Bake for 7-9 minutes until bottoms are golden brown. Cool for 5 minutes on pan, then transfer to a wire rack to cool completely.
Spread half the cookies with nutella then smoosh with another cookie to create a sandwich.