Cookies: Preheat oven to 375 degrees. In a large bowl with mixer beat butter, peanut butter, and sugars until light and fluffy, about 30 seconds on medium-high speed. Lower mixer to medium and add eggs and vanilla continuing to mix until combined. Turn mixer to low and add in flour, baking soda and baking powder. Mix until combined. Refrigerate dough for 1 hour.
Form chilled dough first into 1 inch balls. Roll the dough balls in sugar and place on baking sheet about 2 inches apart. Using a fork press down on cookie creating a criss-cross pattern.
Bake for 6-8 minutes until edges are lightly golden. Cool on baking sheet 2-3 minutes and then transfer to wire rack to continue cooling.
Make the filling. In a large bowl beat butter and peanut butter together until smooth. Add in powdered sugar and beat until smooth. Add one tbsp of milk at a time until you get your desired consistency.
Spread a heaping tablespoon of filling onto the bottom of one of the peanut butter cookies and then top with another cookie to create sandwich.
Peanut Butter Ganache Sandwich Cookie Option - If you prefer a chocolate filling option, this Peanut Butter Ganache Sandwich cookies are fabulous! It's dark chocolate ganache sandwiched between two peanut butter cookies.
/3 cup heavy cream
oz of dark chocolate (I just used Nestle Dark Chocolate Chips but you can use any chocolate you want!)
Place chocolate in a heat proof bowl. Boil the heavy cream over a medium heat and then pour over the chocolate.
Let it sit for a few minutes, and then mix until smooth. Chill for about 1 hour or until it is thicker and more like spreadable filling. Spread a heaping tablespoon of filling onto the bottom of one of the peanut butter cookies and then top with another cookie to create sandwich. Enjoy!