Preheat oven to 180°C (350°F) and grease and flour a 9-inch round springform pan.

Wash the orange thoroughly, remove the stem end and any seeds, and cut the entire fruit including the peel into small chunks.

Place the orange chunks into a food processor or high-speed blender and process until a smooth, uniform puree is achieved.

In a large mixing bowl, beat the eggs and granulated sugar together until the mixture is pale, thick, and doubled in volume.

Gradually stream in the vegetable oil and vanilla extract while continuing to whisk at a low speed.

Fold the orange puree into the wet mixture until evenly distributed.

Sift the flour, baking powder, and salt over the wet ingredients and gently fold together until no dry streaks remain.

Pour the batter into the prepared cake pan and smooth the surface with a spatula.

Bake for 45 to 50 minutes or until a wooden skewer inserted into the center comes out clean.

Allow the cake to cool in the pan for 10 minutes before transferring to a wire rack to cool completely.

Dust the cooled cake with powdered sugar before serving.