Preheat oven to 325 degrees F. Generously grease Bundt pan with butter. In small bowl, combine 1 cup white sugar with cinnamon, mixing well, and evenly coat pan with approximately 1/3 cup of mixture (will form crunchy crust when baked); set aside remainder. In separate bowl, sift together flour, baking powder, baking soda and salt; set aside. In large bowl, cream butter on medium speed for 1 minute. Add 1 cup white sugar and mix for 3 minutes until light and fluffy. Add brown sugar and mix for 2 minutes. Add eggs 1 at a time, beating each for 1 full minute. Stir in vanilla. Add flour mixture alternately with sour cream; beat well. Spread 1/2 of batter into prepared pan. Sprinkle approximately 1/3 cup of cinnamon sugar mixture over batter in pan. Spread remaining batter into pan and sprinkle remaining cinnamon sugar mixture over top. (If you run out of cinnamon sugar, you can mix 1/4 cup white sugar and 1/2 teaspoon cinnamon together for top of cake.) Bake in preheated oven for 55 to 65 minutes, or until toothpick inserted into cake comes out clean. Allow to cool for 10 minutes before inverting onto wire rack to cool completely.