First, there were the Fluffernutter Cookies. Now, there are these Buckwheat Peanut Butter and Banana Shortbread Cookies. Apparently I just like to throw the flavors of my favorite peanut butter-based sandwiches into cookie form. I just can’t help it. Where the Fluffernutter Cookies were heavily inspired by a nostalgia-inciting sandwich, these take after one of …