Line baking sheets with parchment paper or silicone mats.
In a large bowl whisk together the flour, 1 teaspoon chai spice, baking soda and salt; set aside.
In a mixer cream together the butter, cashew butter and sugars until lightened and fluffy, about 2 minutes.
Add the egg, milk and vanilla and mix until incorporated. Stir in the flour mixture and mix until a dough forms. Scrape sides of bowl to make sure everything is mixed evenly.
Wrap and chill the dough about 30 minutes so it's easier to work with. Heat the oven to 350ºF.
Mix together ½ cup extra sugar and 1 teaspoon chai spice in a small bowl. Then scoop the dough into 1-tablespoon-size balls (I used a small cookie scoop). Roll the balls in chai sugar and place about 1 inch apart on the baking sheets.
Bake until just done, but not browning, 8 to 10 minutes.
Immediately place a chocolate disk in the center of each cookie, gently pressing down. Let cool for about 15 minutes before moving to a cooling rack to cool completely.
Notes
Storage: The cookies can be stored in an airtight container at room temperature for 3 to 4 days. *If using Hershey Kisses, make cookies 2-tablespoon-size and bake 1 to 2 minutes longer.