In a large bowl, mix the flour, baking powder, baking soda and salt.

In another bowl, beat the sugar, sour cream, eggs and vanilla until well blended. Stir into the flour mixture just until moistened. Fold in the apples and 1 cup pecans.

Transfer to a greased 9x5-inch loaf pan. Bake at 350° for 50-55minutes or until a toothpick comes out clean. Cool in pan for 10 minutes. Remove to a wire rack to cool.

In a saucepan, bring butter and brown sugar to a boil. Cook and stir for 1 minute. Spoon over bread. Sprinkle with remaining pecans.