Heat the oven to 350°F (175°C). Grease the loaf pan and line with a parchment sling. Whisk flour, baking powder, salt, and cardamom.
Rub orange zest into granulated sugar until fragrant. Beat with softened butter for 3 minutes, scraping the bowl, until light and creamy.
Beat in eggs one at a time and add vanilla. Whisk sour cream and cake orange juice separately until evenly blended.
Add the dry mixture in three stages, alternating with the sour cream mixture. Use low speed and stop once no flour streaks remain.
Spread the batter evenly in the pan. Bake 50–60 minutes until a center skewer shows no raw batter and the top springs back gently.
Tent with foil if browning too quickly. Cool in the pan 15 minutes, then lift onto a rack and cool fully, about 1 hour.
Whisk powdered sugar with 1 tablespoon glaze orange juice. Add more juice a teaspoon at a time until a thick drizzle forms.
Spoon over the cold loaf and allow to settle before slicing. Cut with a serrated knife, wiping away glaze buildup between cuts for a neat edge.
