Preheat oven to 350° F. Grease a 9x5x3-inch loaf pan. In a large mixing bowl beat together granulated sugar, sour cream, eggs, and vanilla on low speed of an electric mixer until combined, then beat on medium speed for 2 minutes.
Stir together flour, baking powder, and soda; add to sour cream mixture, beating on low speed until combined. Stir in apple and 1/2 cup of the pecans. Turn into prepared loaf pan. Sprinkle with remaining chopped pecans; press lightly into batter.
Bake in preheated oven for 55 to 60 minutes, or until a wooden toothpick inserted in center comes out clean. If necessary, cover loosely with foil the last 10 minutes of baking to prevent over browning. Cool in pan on a wire rack for 10 minutes.
Meanwhile, in a small saucepan combine butter and brown sugar; cook and stir until mixture comes to a boil. Reduce heat and boil gently for 1 minute. Remove bread from pan. Drizzle top with brown sugar mixture; cool.
Servings: 1 loaf