In a medium-sized bowl, stir together the melted butter, brown sugar, and pecans. Set aside.
Preheat the oven to 350°F. Use a brush and shortening to carefully grease a Bundt pan. Then dust it with flour.
In a mixing bowl, beat the softened butter and granulated sugar until light and fluffy, about 2 to 3 minutes. Scrape down the sides of the bowl as necessary.
Add the eggs one at a time, beating well after each addition. Beat in the sour cream and vanilla until combined.
In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Gradually add the dry ingredients to the butter mixture, beating until just combined.
Spoon half of the batter into the prepared pan and spread evenly around the pan.
Sprinkle ½ of the prepared pecan mixture over the batter.
Add the remaining batter to the pan. Then add the remaining pecan mixture.
Bake for 40 minutes or until a toothpick inserted comes out clean. Cool in the pan for 10 minutes and then turn the cake out of the pan and let it cool completely.
Sprinkle powdered sugar over the cake.