Make the peanut butter filling: In a small bowl, mix together the peanut butter and powdered sugar until smooth and well combined. Set aside.

1. Prepare the cookie dough: In a medium bowl, whisk together the flour, baking soda, and salt. Set aside. In a large bowl, beat the softened butter with the granulated sugar and brown sugar until creamy and smooth. Add the egg and vanilla extract, beating until combined. Gradually add the dry ingredients to the wet mixture, stirring until the dough comes together. If using, fold in the chocolate chips.
2. Assemble the cookies: Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper. Take about 1 tablespoon of cookie dough and flatten it into a disk shape in the palm of your hand. Place a teaspoon of the peanut butter filling in the center of the dough disk. Gently fold the edges of the cookie dough around the peanut butter, sealing the filling inside. Roll it into a ball. Place the dough balls on the prepared baking sheet, spacing them about 2 inches apart.
3. Bake the cookies: Bake the cookies for 10-12 minutes, or until they are slightly firm around the edges but soft in the center. Let the cookies cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.
4. Serve and enjoy: Once cooled, serve and enjoy these delicious, gooey, peanut butter-stuffed chocolate cookies!