Preheat oven to 350°F (175°C).
Cut a length of parchment paper long enough to line the bottom of the loaf pan with extra hanging over the sides (this creates a "sling" for easy removal).
Spray the pan with nonstick cooking spray, then press the parchment paper into the pan. The spray helps it stay in place.
In a small bowl, combine the granulated sugar and orange zest. Rub them together vigorously with your fingertips for about 30 seconds until the sugar becomes fragrant and slightly damp. This extracts the essential oils from the zest for maximum orange flavor.
½ cup granulated sugar, 1 Tbsp orange zest
In a large bowl, whisk together the flour, baking soda, baking powder, salt, cardamom, brown sugar, and the orange-infused sugar until well combined. Break up any brown sugar clumps with your fingers if needed.
1¾ cups all-purpose flour, ½ tsp baking soda, ½ tsp baking powder, ½ tsp salt, ¼ tsp ground cardamom, ¼ cup packed light brown sugar
In a medium bowl, whisk together the melted butter, buttermilk, eggs, and vanilla extract until smooth and well combined.
½ cup unsalted butter, 1 cup buttermilk, 2 large eggs, 1½ tsp vanilla extract
Pour the wet ingredients over the dry ingredients.
Using a rubber spatula or wooden spoon, gently fold the mixture together just until no dry flour remains. Do not overmix, the batter should look slightly lumpy. Overmixing will make the bread tough.
If using fresh cranberries, rinse and pat them completely dry. If using frozen, do not thaw, use them straight from the freezer.
1 cup fresh or frozen cranberries
Place cranberries in a small bowl and toss with 1 Tbsp flour until each berry is lightly coated. This prevents them from sinking to the bottom.
1 Tbsp all-purpose flour
Gently fold the floured cranberries into the batter, being careful not to overmix.
Pour the batter into the prepared loaf pan and smooth the top with a spatula.
Bake for 50-55 minutes. The bread is done when the top is deeply golden brown, a toothpick inserted in the center comes out with just a few moist crumbs (not wet batter), and the internal temperature reads 200-205°F on an instant-read thermometer.
If the top is browning too quickly (check around 40 minutes), loosely tent the pan with aluminum foil for the remaining bake time.
Remove from the oven and let the bread cool in the pan on a wire rack for 20 minutes.
Use the parchment paper sling to lift the loaf out of the pan, then transfer to the wire rack to cool completely (about 30-45 minutes more).