Preheat oven to 375 degrees F. Spray an 8" square pan with cooking spray.
In a large mixing bowl, beat butter and sugar until fluffy, about a minute.
Add egg, vanilla and 1 Tablespoon of the chai tea.
In a separate bowl, whisk together flour, salt, baking soda and spices.
Add flour mixture to egg mixture and mix just until combined.
Spread in prepared pan.
Bake for 10-15 minutes or until just lightly golden. Take care not to over bake or you'll have dry bars.
Allow to cool completely.
To make frosting, beat butter and cream cheese until smooth and fully combined and fluffy.
Add the sugar, pinch of salt and vanilla and beat until combined.
Add 1-2 Tablespoons of tea, a little at a time, and beat until frosting is desired consistency.
Frost cooled bars. Sprinkle with cinnamon, if desired. Store in refrigerator, tightly covered. You can serve cold, but I think the flavor is best at room temperature.