Prep: Preheat your oven to 350℉. Line a few cookie sheets with parchment paper. If you plan on freezing the dough, beat in 1 tbsp of milk in at the end, after you've mixed in the dry ingredients.
Make Cookie Dough: Melt the butter in a large mixing bowl, then whisk in the peanut butter until no lumps remain. Add the sugars, and whisk to combine. Add the eggs and vanilla, and whisk until smooth and combined, about 30-45 seconds. Stir in the dry ingredients last. (You will need to use some elbow grease here for it to come together - I promise it will! - or use your mixer for this last bit.)
15 tbsp salted butter, melted, 3/4 cup + 2 tbsp creamy peanut butter, 3/4 cup dark brown sugar, packed, 3/4 cup granulated sugar , 2 large eggs, at room temperature , 1 and 1/2 tsp vanilla extract , 3 cups all-purpose flour, spooned & leveled or weighed out , 1 tsp baking soda, 1 tsp baking powder, 1/2 tsp salt, 1 tbsp milk
Make Dough Balls: Roll dough into balls that are 35 grams (about 1 generous tbsp) in size. Roll the balls in granulated sugar or festive sprinkles.
1/2 cup granulated sugar , 1 cup non pareil sprinkles
Bake: Bake 8 cookies per cookie sheet, leaving a little space for them to spread (but they won't spread a lot). Bake for 7 minutes. The edges will appear just set and the center will be a little puffy but they may look like they need another minute - don't do it! Peanut butter cookies can dry out easily, so don't over bake. This is a short bake time, but it yields perfectly soft-baked cookies once they cool!
36 unwrapped hershey's kisses
Finish Cookies: Let cookies cool on the pan set on a cooling rack for about 3-5 minutes before pressing a hershey's kiss on top of each cookie. Dig in while the cookies are still warm, or let them cool completely before enjoying.
Serve & Store: Store completely cooled cookies in an airtight container at room temperature for 4-5 days.
Make-Ahead Tip: Cookie dough balls can be made, rolled in sugar/sprinkles, and frozen on a lined baking sheet. Once frozen, transfer to a freezer bag and freeze for 1-2 months. Bake from frozen, adding 1-2 minutes if needed.