Preheat oven to 350° F. Line an 8x8 baking with parchment paper and spray it with cooking spray.
Whisk together the flour, baking powder, cream of tartar, salt and spices in a bowl and set aside.
In the bowl of a stand mixer with the paddle attachment or with a handheld mixer, beat the butter and sugar until smooth. Add in the egg and vanilla extract and beat until combined, scraping down the sides of the bowl once.
Slowly add in the dry ingredients and beat together on low speed just until combined.
Spread the batter evenly into the prepared 8x8 baking pan.
Sprinkle the cinnamon-cardamom sugar evenly over the top of the batter.
Bake the bars for 18-20 minutes or just until a toothpick inserted in the center comes out clean, don't overbake or they will be dry.
Notes
The batter will be sticky. Spraying the back of a rubber spatula with cooking spray and using it to spread out the batter will make it easier.