Prep and Cream Butter Base: Preheat your oven to 180°C (350°F) and line a 9x5-inch loaf pan with parchment paper.
In a large bowl, add the room-temperature butter, granulated sugar, orange zest, vanilla extract, and kosher salt. Beat with an electric hand mixer on medium speed for 3 to 4 minutes, until light, fluffy, and pale.
Mix in Wet Ingredients: Add the sour cream and eggs one at a time, beating well after each addition until fully incorporated into a smooth batter.
Add Dry Ingredients and Juice: Add half the cake flour, half the baking powder, and half the fresh orange juice.
Mix on low speed until just combined. Add the remaining flour and orange juice, mixing until just combined and no dry flour streaks remain.
Bake: Pour the batter into the prepared loaf pan and spread it evenly with an offset spatula.
Bake for 45 to 50 minutes, or until a toothpick inserted into the center comes out clean. Cool in the pan for 15 minutes, then transfer to a wire cooling rack to cool completely.
Make the orange glaze
Mix and Glaze: In a medium mixing bowl, whisk together the powdered sugar, fresh orange juice, yogurt, and a pinch of kosher salt until smooth and silky.
Drizzle the cooled cake with the glaze, let it set for a few minutes, then slice and serve.
Notes
Weigh Your Ingredients: For exact accuracy and the softest crumb, weigh ingredients in grams using a digital kitchen scale rather than measuring cups.
Room-Temperature Dairy & Eggs: Ensure butter, eggs, and sour cream are all at room temperature so the batter emulsifies smoothly without breaking or curdling.
Orange Flavor Hack: Rub the fresh orange zest into the granulated sugar with your fingertips before creaming. This releases essential aromatic oils for maximum orange flavor.
Cake Flour Substitute: If you do not have cake flour, remove 2 tablespoons of flour from 1 cup of all-purpose flour, replace with 2 tablespoons of cornstarch, and sift together twice before measuring.
Pan Size & Timing: This recipe is written for a standard 9x5-inch loaf pan. Start checking for doneness with a toothpick at the 45-minute mark to prevent over-baking and drying out the crumb.
Cool Before Glazing: Allow the loaf to cool completely to room temperature before pouring the glaze over top; otherwise, the glaze will melt into the cake rather than setting into a opaque glaze.
Storage & Freezing: Store covered at room temperature for up to 3 days or refrigerated for up to 5 days. Wrap unglazed loaves tightly in plastic wrap and freeze for up to 3 months. Thaw at room temperature before adding the glaze.