Preheat oven to 375° F. Line two baking sheets with parchment paper.
Whisk together the flour blend, baking soda, baking powder, and salt in small bowl. Set aside.
In the bowl of a stand mixer or with an electric mixer, beat butter and sugars until well combined. Add the peanut butter and cream until light and fluffy, about 3 minutes.
Add the egg, milk, and vanilla and mix to combine.
Reduce the speed to low and slowly add the flour mixture just until well incorporated. Refrigerate for at least 2 hours.
Scoop dough with cookie scoop or small spoon and roll into balls (about one inch in diameter). Dredge balls in granulated sugar (if desired) and place about 2 inches apart on prepared baking sheets.
Bake for 7-8 minutes, or until puffed up. Don't overbake as they won't be as soft upon cooling.
Remove baking sheets from oven and immediate place unwrapped kiss in center of each cookie, pressing lightly. Allow cookies to cool on baking sheet for about 5 minutes and then remove to wire rack to cool completely.
Cookies will keep in an airtight container at room temperature for 4-5 days, or can be frozen, well wrapped, for up to 3 months.