In a small bowl, whisk together the flour, baking soda, and salt. Set aside.
In a large bowl, beat together the butter and both sugars until light and creamy, about 2-3 minutes. Beat in the egg, milk, and vanilla. Gradually add in flour mixture. Refrigerate for 1 hour or until firm.
Preheat oven to 375F degrees. Line 2-4 baking sheets with parchment paper.
Pour some sugar into a small bowl. Shape the dough into 1-inch balls, roll them in the sugar, then place them on the trays. Bake 8-10 minutes or until lightly browned. Immediately press one marshmallow half cut-side down onto each cookie, gently pressing down. Wait a few minutes then place the cookies onto a cooling rack. Repeat until all of the cookies are baked.
Turn the oven to broil. Place the cookies back onto the cookie sheets and broil until toasted. This process may happen quickly, so do not leave them unattended. If your oven has hot spots, you may need to rotate the trays until all of the marshmallows are toasted. Once toasted, press a chocolate kiss into each one. Let cool completely.
*If you cannot find cookie butter, substitute peanut butter
Recipe by Chocolate Moosey at http://www.chocolatemoosey.com/2013/02/03/smores-blossom-cookies/