Preheat oven to 350°F (175°C). Grease a standard 9x5-inch metal loaf pan and line with parchment paper, leaving an overhang on the sides for easy lifting.

In a large mixing bowl, combine granulated sugar and fresh orange zest. Use your fingertips to rub the zest into the sugar for 1 minute until fragrant and moist (this releases essential citrus oils).

Whisk in the flour, baking powder, baking soda, and salt until evenly distributed.

In a separate medium bowl, whisk together orange juice, melted butter, sour cream, egg, and vanilla extract until smooth.

In a small bowl, toss chopped cranberries with 1 tablespoon of flour to coat them completely (this keeps them evenly suspended throughout the loaf).

Pour the wet ingredients into the dry ingredients. Stir with a spatula just until barely combined—do not overmix! Gently fold in the floured cranberries.

Spread batter evenly into the prepared loaf pan. Bake at 350°F (175°C) for 50 to 58 minutes, or until golden brown and a toothpick inserted into the center comes out clean.

Cool in the pan on a wire rack for 15 minutes, then use parchment handles to lift loaf out onto the wire rack to cool completely.

Whisk powdered sugar, orange juice, and orange zest together until a thick, glossy glaze forms. Drizzle generously over the cooled loaf, let set for 10 minutes, slice, and enjoy!