Preheat oven to 325°F (165°C).
Generously grease and flour a 10-inch Bundt pan.
In a small bowl, mix brown sugar, cinnamon, and pecans. Set aside.
In a large bowl, cream butter and sugar until light and fluffy (~3 mins).
Add eggs, one at a time, beating well after each.
In another bowl, whisk flour, baking powder, and salt.
Alternately add dry ingredients and sour cream to the batter, mixing until smooth.
Stir in vanilla extract.
Pour ⅔ of the batter into the Bundt pan.
Sprinkle the cinnamon-sugar-pecan mixture evenly over the batter.
Top with the remaining batter and smooth gently.
Bake for 60-70 minutes, or until a toothpick comes out clean.
Cool in the pan for 15 minutes, then invert onto a wire rack to cool completely.
Slice and enjoy as is or with a dusting of powdered sugar!
