Unwrap the chocolate kisses and place in the freezer while making the dough.
In a mixing bowl, combine the flour, baking soda, baking powder, and salt. Whisk together. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment, add the butter, brown sugar, granulated sugar, and peanut butter until smooth and creamy, about 2 minutes.
Add the egg, egg yolk, vanilla, and milk and mix until light and creamy, approx. 2 minutes.
Add the flour mixture and mix until just combined. Chill the dough for at least 30 minutes.
Preheat the oven to 375℉. Line a sheet pan with parchment paper. Set aside.
Using a 1-tablespoon sized cookie scoop, form the dough into balls and roll in granulated sugar. Place 2 inches apart on the prepared baking sheet. Flatten the dough slightly.
Bake 8-9 minutes until just set. The middle will look slightly underdone. Allow to cool for 1 minute. Press a chocolate kiss into the center of each cookie.
Cool cookies until chocolate kiss is firm. Store in an airtight container for 4-5 days.
Notes
Over baking or adding too much flour will cause cookies to be dry. Make sure to properly measure the flour using the spoon, scoop, and level method. Bake the cookies until just lightly brown around the edges. The middle will look slightly underdone.
The cookie dough can be made and chilled as much as 72 hours before baking. The dough also freezes well. Scoop the dough into balls and place on a parchment-lined sheet pan. Freeze until firm. Then transfer the dough balls to a freezer-safe zipper-top bag. Store in the freezer for up to 2 months. To bake: thaw at room temperature. Roll the dough in sugar and bake according to the recipe directions.
Use room temperature ingredients. Butter and eggs will incorporate more fully and smoothly when brought to room temperature first.
Don't overmix. When adding the dry ingredients, mix until just combined. Overmixing the flour will create a tough cookie.
Chill the dough. This helps to prevent the cookies from spreading during baking. It also allows the flavors to blend and enhance.
Line baking sheets with parchment paper. This prevents the cookies from sticking and allows for easy clean-up. Silicone baking mats can also be used.
Freeze the chocolate kisses while you make the cookie dough. This helps them keep their shape and prevents them from getting too soft when placed on the warm cookies.
Customize for any season by rolling the cookie dough in different colored sugars or sprinkles.