1. Preheat oven to 350 degrees and grease a 10 inch bundt pan.

Cake

1. Whisk together flour, baking powder, and salt in large bowl.  Set aside.

2. In a stand mixer, beat the butter, brown sugar, and granulated sugar together until creamed.  This should take about 2 minutes.  Add the 5 eggs, sour cream, and vanilla.  Beat on medium speed until combined.

3. Scrape the sides of the bowl with rubber spatula as needed.  It might alarm you that the mixture looks a bit curdled - this is how its supposed to look before the dry ingredients make an appearance in the mix.

4. Pour the dry ingredients into the wet ingredients.  Pour in milk, then beat on medium speed until the batter is combined.  The batter will be thick with a smooth look.

Cinnamon Chai Swirl

1. Mix the swirl ingredients together in a medium bowl with a wooden spoon or whisk.

Putting it together

1. Pour half of the cake batter into bundt pan.  Pour the swirl ingredients evenly on top of the first layer of batter and smooth out evenly with a spoon.  Cover the swirl ingredients with the rest of the batter.  Spread the batter out evenly.

2. Bake for 55-70 minutes, depending on your oven.  When a toothpick inserted into middle of cake comes out clean or with a few moist crumbs, the cake is done.

3. When done, remove from oven and cool in pan for 2 hours.  At the end of 2 hours, carefully turn the bundt pan over and place bundt cake on a wire rack or serving dish.  Allow to cool completely.

Brown Butter Icing

1. Cut up the butter into 6 pieces and place in a skillet (preferably light colored so you can see when the butter browns). 

2. Melt the butter over medium heat, stirring occasionally.  Once melted the butter will begin to guard.  Keep stirring occasionally.  After about 5 minutes, the butter will begin to brown - you will see little brown specks at the bottom of the pan and there will be a nutty aroma overtaking your kitchen.  

3. When this happens, remove pan from heat and allow to cool for 5 minutes.  After 5 minutes, whisk in the rest of the icing ingredients until smooth.  If needed, you can add more powdered sugar for a thicker consistency or more milk if you need to thin the icing out.