01 -
Preheat oven to 350°F (175°C). Generously grease a 10-cup Bundt pan with butter or baking spray, ensuring all crevices are coated.
02 -
In a medium bowl, whisk together flour, baking powder, baking soda, salt, and 1 teaspoon ground cinnamon until evenly blended.
03 -
Using a mixer on medium speed, beat softened butter and granulated sugar in a large bowl for 3 to 4 minutes until light and fluffy. Add eggs one at a time, mixing thoroughly after each addition, then blend in vanilla extract.
04 -
Add one third of the flour mixture to the butter mixture and mix until just combined. Blend in half the sour cream, then repeat the process—alternating flour and sour cream and finishing with the remaining flour mixture. Do not overmix.
05 -
In a small bowl, combine packed brown sugar with 1 tablespoon ground cinnamon, mixing until uniform.
06 -
Pour half of the batter into the prepared Bundt pan and spread evenly. Sprinkle half the cinnamon-sugar mixture over the batter. Layer with remaining batter and sprinkle the rest of the cinnamon-sugar. Gently swirl through the mixture with a knife using 3 to 4 figure-eight motions.
07 -
Bake in the center of the oven for 45 to 55 minutes, or until a toothpick inserted into the center comes out clean. Cool in the pan for 10 minutes before inverting onto a wire rack.
08 -
Allow the cake to cool completely. Dust evenly with powdered sugar before slicing and serving.