Butter a 9x5x3-inch pan.

Preheat oven to 350 degrees F (175 degrees C).

Cream butter, add sugar slowly, and continue to beat until light and lemon-colored.

Beat in eggs.

Sift flour with salt, baking soda, and baking powder.

Add to the butter mixture alternately with the buttermilk, beginning and ending with the dry ingredients.

Stir in the apples, nuts, and vanilla.

Spoon batter into prepared pan.

Bake in a preheated 350 degree F (175 degrees C) oven for 50-60 minutes, until the loaf pulls away slightly from the sides of the pan or until a cake tester comes out clean.

Cool in the pan for about 5 minutes, then loosen from pan and turn onto a rack to cool completely before slicing.