Preheat oven to 375F. Line two baking sheets with parchment paper and set aside. Place 1/4-1/2 c. granulated sugar in a small bowl and set that aside as well.

In the bowl of a stand mixer fitted with the paddle attachment, cream together butter, sugars, and 1/4 c. peanut butter on medium speed. Scrape down sides of the bowl. Beat in vanilla and egg. Sift flour, cocoa powder, salt, and baking soda into bowl. Beat on medium-low until dough begins to come together, 1-2 minutes.

In a separate bowl, cream together (use either the stand mixer or a hand held mixer) remaining 1/2 c. peanut butter and confectioners sugar.

Using a 1 1/2 Tbs. ice cream scoop, portion out dough into equal sizes. With clean hands, roll each into a ball. Flatted between your palms. Pinch off pieces of the peanut butter filling - about the size of a dime (adjust more or less depending on whether you can seal the peanut butter inside the dough). Place in center of the chocolate dough. Fold dough over and pinch together at seams to seal. Roll into a ball. Roll ball in a small bowl of granulated sugar. Set onto prepared baking sheet. Continue with remaining dough, placing cookies about 2 inches apart. When baking sheets are filled, flatten each cookie slightly, with the palm of your hand or the flat bottom of a juice glass.