Preheat oven to 350 degrees, and grease your loaf pan.
Whisk dry ingredients – flour, baking powder, baking soda, and salt – together in a mixing bowl. Once combined, stir in orange zest and cranberries. Set aside.
Beat wet ingredients – butter, sugar, and egg – in a large bowl until smooth. Stir in orange juice. Beat in flour mixture until just moistened.
Pour full mixture into loaf pan. Top with extra cranberries as desired.
Bake until a toothpick comes out of center clean, about 1 hour. Let stand 10 minutes, then move out of pan onto a wire rack to cool.
Once completely cool, add icing, serve or wrap in plastic wrap to store.