1. Preheat your oven to 350°F (175°C). Grease a 9×5-inch loaf pan or line it with parchment paper.
2. In a large mixing bowl, combine the granulated sugar and fresh orange zest. Use your fingertips to rub the zest into the sugar until fragrant. This helps release the natural orange oils for a stronger citrus flavor.
3. Add the melted and slightly cooled butter, eggs, sourdough discard, Greek yogurt, orange juice, and vanilla extract to the orange sugar. Whisk until smooth and well combined.
4. In a separate bowl, whisk together the all-purpose flour, baking powder, baking soda, and salt.
5. Gently fold the dry ingredients into the wet ingredients until just combined. Avoid overmixing. The batter should be thick but scoopable.
6. Toss the cranberries in a tablespoon of flour to avoid them from sinking and gently fold them into the batter.
7. Transfer the batter to the prepared loaf pan and spread evenly.
8. Bake for 55–60 minutes, or until a toothpick inserted into the center comes out clean or with a few moist crumbs. The center should reach approximately 200–205°F. If the top begins browning too quickly, loosely tent with aluminum foil.
9. Allow the loaf to cool in the pan for approximately 15 minutes before transferring to a wire rack to cool completely.

Make the orange glaze

1. In a small bowl, whisk together the powdered sugar, fresh orange juice, orange zest, and optional vanilla extract until smooth. Add additional orange juice a teaspoon at a time if needed to reach your desired consistency.
2. Once the loaf has completely cooled, drizzle the orange glaze over the top. Allow the glaze to set slightly before slicing and serving.
3. Store the glazed loaf in an airtight container at room temperature for up to 2 days or refrigerate for up to 5 days.
4. For best results, freeze the loaf without the glaze. Wrap tightly and freeze for up to 3 months. Thaw completely before glazing.