1. Blend chai spice mix. Place in a container with a tight lid.
2. Warm the milk over low heat just until boiling, stirring frequently to prevent scorching.
3. Pour the boiling milk into a heat-proof mason jar and add chai tea bag. Steep until mixture reaches room temperature.
4. Preheat the oven to 350 degrees. Grease and flour the sides and bottom of a half sheet cake pan.
5. In a mixing bowl, add sifted cake flour, baking powder, baking soda, salt, and 2 tbs of chai spice mix into a bowl. Whisk to combine.
6. In a stand mixer, cream butter and sugar until fluffy.
7. Add eggs, vanilla, and sour cream and whip on high until well combined. Remember to scrape the sides of the bowl at least once!
8. Add dry ingredients and mix until just combined.
9. Add the chai milk mixture slowly and mix until just incorporated. Scrape the sides of the bowl and check for lumps. Mix until thick but still pourable.
10. Pour batter evenly into cake pan.
11. Bake for 30-35 minutes until a wooden skewer emerges clean from the cake.
12. Let cool in the pan.
13. Using a highball glass, cut circles of cake.
14. Place a circle of cake in the glass, press down lightly till it reaches the bottom of the glass.

For whipped cream and plating:

1. Whip heavy cream until stiff peaks form.
2. Add powdered sugar and freeze-dried blueberry powder.
3. Whip until well combined and firm.
4. Spread blueberry whipped cream over the cake. Wipe the glass down.
5. Add another layer of cake and blueberry whipped cream.
6. Wipe glass.
7. Repeat one more time to get three layers.
8. Dust with freeze-dried blueberry powder. Garnish with fresh berries. Enjoy!