Preheat oven to 375F. Line two baking sheets with baking mats or parchment paper.

Whisk together flour, baking soda and salt; set aside. With electric mixer, beat peanut butter and shortening  until well blended, 2 minutes. Add sugars and beat until fluffy. Add egg, milk and vanilla, and beat well. Reduce speed to low and gradually beat flour into peanut butter mixture until just combined.

Shape dough into 1-inch balls (small cookie scoop) and roll in sugar to coat. Place on baking sheets and bake 8 -10 minutes, until lightly browned. Remove from oven and immediately press a chocolate kiss into center of cookie. Cool 5 minutes, remove to a wire rack to cool completely. Cookies can be stored in airtight container at room temperature up to 1 week.