I made homemade buttercream icing for Charlotte's birthday cupcakes (a post I hope to put up here soon) and have since then been a little obsessed with icing. Eating leftover cupcakes cold from the fridge with ice cream on top was a little slice of heaven during the past week of 100-degree temperatures. So when I saw this recipe for Peanut Butter Sandwich Cookies in a cookbook ('wichcraft) that my mom brought down, and saw that it called for sandwiching two rich, sweet, nutty peanut butter cookies together with a peanut butter buttercream, I knew I had to make it.
My mom took that cookbook home with her, but I found a similar recipe online here. That's the one I followed, and I was very pleased with the results. The authors of that recipe suggest using nutella or jelly to sandwich the cookies, but please, please don't listen to them. Make the buttercream. Use the buttercream. LOVE the buttercream.
Incidently, I used Simply Jif for these cookies, which I understand to have a little less added sugar than other peanut butters. It worked just fine, and I didn't add extra sweetening at all. If you use regular peanut butter, you might want to taste the dough for sweetness before adding all the sugar, as it seemed like it might be too much with regular peanut butter.