• Preheat the oven to 350℉. Grease a 10-inch bundt cake pan (12-cup) by spraying with nonstick coking spray, Baker's Joy spray, or spread softened butter or shortening in it. 

Prepare The Cake Batter

• Combine the dry ingredients by whisking together the flour, baking powder, baking soda, and salt in a medium bowl. Set aside. 
  2½ cups all-purpose flour, 1 teaspoon baking powder, 1 teaspoon baking soda, ¼ teaspoon salt
• In the bowl of a stand mixer using the paddle attachment, or use a large mixing bowl and an electric mixer, cream together the butter and sugar until light and fluffy. About 2 minutes of beating on medium-high speed. 
  1½ cups granulated sugar, 12 tablespoons butter
• Add in the eggs, one at a time, and mix until well combined after each egg addition.
  3 large eggs
• Add the vanilla extract and beat just until combined. 
  2 teaspoons vanilla extract
• Add half of the flour mixture into the butter/sugar mixture and beat on low speed just until combined. Add in the sour cream and beat until combined. Add in the remaining flour mixture and beat on low speed until combined and no flour streaks remain in the cake batter. 
  1 cup full-fat sour cream
• Pour half of the cake batter into the prepared bundt pan. 

Make The Cinnamon Swirl

• In a small mixing bowl, stir together the light brown sugar and cinnamon. Sprinkle it evenly over the cake batter inside the bundt pan. 
  1/4 cup packed light brown sugar, 1 tablespoon ground cinnamon

Assemble Bundt Cake & Bake

• Spoon the remaining cake batter over top the cinnamon layer, making sure to cover all the cinnamon layer in the cake batter - carefully use a spoon, if needed, to spread it out. 
• Bake for 40-50 minutes or until a toothpick inserted into the top center of the cake comes out clean. 
• Remove the bundt cake from the oven and allow it to cool for 10 minutes before inverting it/flipping it onto a serving plate. 
• Once the cake has cooled to room temperature prepare the simple glaze. In a small bowl stir together the powdered sugar, milk, and vanilla extract until a smooth and pourable glaze forms.

  Once the cake has cooled to room temperature, pour the glaze over top of the cake. Enjoy!
  2 cups powdered sugar, 2-4 tablespoons milk, 1 teaspoon vanilla extract