There is just something so sweet about a thumbprint cookie.  Growing up my mom would buy the shortbread ones with the cutest little chocolate center, and then sometimes she would make a peanut butter cookie with a chocolate kiss in the center so for this Valentines Day I wanted to make a chocolate cookie version. Chocolate, please I am all about chocolate anything and this chocolate cookie with a chocolate kiss in the center is a perfect chocolate treat and an even more perfect treat for Valentines Day. To make these cookies decadent I used dark cocoa powder for added richness, buttermilk for a little tang and tartness (which I love in a cookie),…