Preheat the oven to 350. Spray a bread pan with cooking spray, then line with parchment, overlapping the pan on two sides.
Add the sugar and orange zest to a large bowl. Rub the zest into the sugar using your fingers, until fragrant. Whisk in the flour, baking powder, and salt. Toss the cranberries with the flour mixture to coat.
In a small bowl, whisk together the buttermilk, oil, vanilla, eggs and orange juice. Pour the wet ingredients into the dry ingredients, and mix until just combined.
Pour the batter into the prepared pan. Bake 60-75 minutes, or until golden brown on top and a toothpick inserted into the center comes out clean. Let cool 10-15 minutes.
To make the glaze, whisk all glaze ingredients together. Drizzle over the slightly warm bread, and allow to cool before serving.