Prepare the loaf pan. Tear off a piece of parchment paper slightly larger than your pan. Trace around the base of the pan onto the paper and cut it out with scissors. Grease the bottom of the pan with a small piece of butter, place the cut parchment paper inside, and grease the paper as well. Grease the sides of the pan and sprinkle granulated sugar all over the inside to coat evenly.

Sift the dry ingredients. Sift together the flour and baking powder in a separate bowl and set aside.

Cream the butter and sugar. Place the butter in a large mixing bowl. With the electric mixer on high speed, add the sugar gradually and continue beating for 1 minute until light.

Emulsify the eggs. Add the eggs one at a time, ensuring each egg is fully incorporated before adding the next. Adding the eggs gradually is essential for achieving a light, airy cake texture.

Incorporate the flour. Turn the mixer to low speed, add the orange zest, and gradually stir in the sifted flour mixture. Mix just until a smooth batter forms, then scrape down the sides of the bowl with a spatula to ensure everything is combined.

Bake the cake. Spoon the batter evenly into the prepared loaf pan. Bake for about 30 to 35 minutes, or until the top is golden brown and a skewer or knife inserted into the center comes out clean.

Unmold gently. Remove from the oven and let the cake rest in the pan for 5 minutes. Invert it carefully onto a deep serving plate, then grasp the edge of the parchment paper and gently peel it off.

Make the syrup. While the cake is baking or resting, whisk the orange juice and powdered sugar together in a small bowl until completely smooth and combined.

Glaze and serve. Douse the warm cake evenly with the orange syrup. The cake will absorb most of the syrup, leaving a lovely gloss with a bit of delicious run-off. Let it cool completely. Just before serving, dust with powdered sugar. Happy baking and eating!