These delicious cookies are so fun to share!
Heat oven to 375°F.
Beat butter, peanut butter, and sugar in a stand mixer for about 2 minutes on medium speed. Turn mixer to low and add in egg, milk, vanilla, and red food coloring. Mix for about 30 seconds to incorporate, then turn mixer to medium-high and blend until light and fluffy.
In a separate bowl sift cocoa, flour, baking soda and salt. With mixer on slow add flour mixture to sugar mixture and beat until just combined.
Remove mixer bowl from stand. Shape dough into 1 inch balls. Set on a parchment lined baking sheet.
Roll dough ball in red sanding sugar and place on prepared cookie sheet about 2 inches apart. (If want them extra chewy, chill for 10 minutes in the freezer before baking.)
While baking unwrap Hershey's Kisses. Once cookies are done baking, remove from oven and immediately press a chocolate Kiss into the center of each cookie. The cookie should crack around edges.