In a large bowl combine flour, baking powder, sugar, salt, and baking soda.
In a small bowl blend egg and buttermilk together, and add all at once to the flour mixture. Mix just until moistened. Stir in butter. Pour into prepared loaf pan.
Bake for 60 to 70 minutes, or until a toothpick inserted in the center comes out clean. Cool on a wire rack.