Gather all the ingredients for the recipe.

Wash and dry the oranges thoroughly. Using a fine grater, zest one and a half oranges (only the orange part, not the white pith, as it is bitter). Set aside.

Juice both oranges and set the juice aside.

In a blender, combine the eggs, sugar, vanilla, and oil. Blend for 1 minute.

Turn off the blender and add the flour and baking powder. Blend briefly to mix everything together. Add the orange juice and blend for another minute.

Pour the mixture into a bowl and add the orange zest. Use a spatula to mix everything together.

Pour the batter into the prepared pan and bake in the preheated oven at 350°F (180°C) for about 40 minutes. Check for doneness by inserting a knife or toothpick into the center; it should come out clean and dry.

Once out of the oven, let the cake cool slightly, then remove it from the pan and place it on a wire rack.

Let it cool completely and add your personal touch for presentation.