Preheat the oven to 400°F. Line a baking sheet with parchment paper or a silicone baking mat. Set aside.
Whisk together the ingredients for the chai spice blend in a small bowl.
2 tsp. ground cinnamon, 1 tsp. ground ginger, 1 tsp. cardamom, 1/2 tsp. allspice, 1/2 tsp nutmeg, 1/2 tsp. cloves
In a large bowl, combine the dry ingredients: all purpose flour, cake flour, corn starch, 1 heaping tablespoon chai spice, baking soda, baking powder and salt. Set aside.
2 1/2 cups all-purpose flour, 1 1/2 cups cake flour, 2 tsp. cornstarch, 1 tsp. baking soda, 1 tsp. baking powder, 1 tsp. salt, 2 Tbsp. chai spice blend, divided (recipe below)
Place the cubed butter and sugars into the bowl of a stand mixture and secure the paddle attachment. Turn the mixer on and cream until smooth, about 1-2 minutes.
16 Tbsp. unsalted butter, cold, cubed (1 cup butter), 1 cup sugar, 1/4 cup brown sugar, packed (light or dark)
Add in the eggs, egg yolks and vanilla extract and blend until mixed. Use a rubber spatula to knock off mixture if any is sticking to the sides of the bowl and mix again.
2 large eggs, 2 large egg yolks, 2 tsp. vanilla extract
Gradually add in the dry ingredients, about 1/4 cup at a time. Mix until incorporated.
Roll cookie dough into ~6-7 large balls, or smaller if preferred to get ~20-22 cookies.
Add 1 Tbsp. sugar to the remaining chai spice and roll the cookie dough balls in the chai spice mixture.
Place on baking sheet & bake cookies for ~10-11 minutes for the large cookies or ~8-10 minutes for the smaller cookies. Cool cookies completely before glazing.
For the glaze: Place sifted confectioners’ sugar in a medium sized bowl and add milk and vanilla bean paste. Mix until all of the sugar is incorporated. Add additional milk as needed; glaze should be on the thick side. Spoon glaze over cookies or dunk cookies in glaze. Allow glaze to dry, then enjoy.
1 1/2 cups confectioners' sugar, 3 Tbsp. milk (plus more as needed), 1 tsp. vanilla bean paste