Preheat oven to 350 degrees F (175 degrees C). Spray a 9x13 inch pan with cooking spray. Combine the flour, baking soda and baking powder; set aside.
In a medium bowl, cream together the sugar, butter and eggs until smooth. Add the flour mixture and beat until smooth. Finally, stir in the sour cream and vanilla. In a separate bowl, combine the nuts (optional) brown sugar butter flour and cinnamon.
Spread half of the batter into the 9x13 inch pan. Sprinkle a layer of the nut mixture, then spread the remaining batter and top with the rest of the nut mixture. Spread the melted butter over the top.
Bake in 350 degree oven for 45 minutes or until knife in center comes out clean.