Preheat the oven to 350 degrees, and grease a 9 x 5 - inch loaf pan.
In a medium bowl, whisk together the flour, baking powder, and salt until well combined. Set aside.
In a separate small bowl, use a spoon to mix the sugar and orange zest until the sugar becomes light orange in color. Set aside.
Add to the bowl of a stand mixer (or a large bowl and hand mixer), the buttermilk, oil, orange juice, eggs, and vanilla. Mix on low speed until the ingredients are combined.
Add the flour mixture and the orange zest/sugar mixture. Continue to mix on low speed until all the ingredients are smooth like muffin batter.
Next, add the cranberries and use a wooden spoon or spatula to stir until well incorporated.
Transfer the batter to the greased loaf pan. Place in the oven and baked for 70-75 minutes. If the bread begins to become too brown, place a piece of aluminum foil loosely over the top to prevent burning.
The bread is done when a toothpick inserted in the center comes out with a very light crumb. Remove the bread from the oven and allow to cool for 5-7 minutes before transferring from the pan to a cooling rack.