Big, soft chocolate sugar cookies made with Greek yogurt, topped with a creamy, rich peanut butter frosting. Cookies adapted from my [Big Soft Frosted Sugar Cookies|http://alaskascratch.wpengine.com/2013/03/13/big-soft-lofthouse-sugar-cookies/] recipe; frosting adapted from [Cooking Classy|http://www.cookingclassy.com/2012/03/chocolate-sugar-cookies-with-peanut-butter-frosting-taste-like-reeses/].
In a mixing bowl, stir together the flour, cocoa, baking powder, baking soda, and salt. Set aside.
In the bowl of a stand-mixer fitted with the paddle attachment, cream together the butter and sugar until light and fluffy. Incorporate the eggs, followed by the vanilla, and the yogurt, scraping the sides of the bowl as needed. Gradually add the dry ingredients until it all just comes together. The dough will be sticky.
Divide the dough in half and flatten each half into a disc. Wrap each disc in plastic wrap and refrigerate at least two hours.
Preheat oven to 425, placing oven rack in the middle of the oven. Line cookie sheets with parchment paper.
Unwrap the dough and place it onto a floured work surface. Dust the top of the dough with flour also. Roll the dough to 1/4-inch thickness. Cut the dough with a round cutter (about 2-3-inch size cutter). Place the cookies on the prepared baking sheet and repeat with the remaining dough.
Bake the cookies 6-7 minutes until cooked through and set. Transfer cookies immediately to a cooling rack to cool completely before frosting.
!To Make Frosting:
In the bowl of a stand mixer, fitted with the paddle or whisk attachment, cream together the peanut butter and butter. Add the vanilla and salt. Turn the mixer down to low and add the powdered sugar. At this stage, the mixture will turn crumbly. Add milk gradually until the frosting comes together and becomes light and creamy.
Frost cookies (I used a piping bag with a large round tip in a round swirling motion, then used a small off-set spatula to lightly spread the frosting). Sprinkle the cookies with sprinkles as desired directly after frosting so that the sprinkles will adhere.
Store cookies in an airtight container.