Grandma's Orange cake (Bolo de Laranja)

1. Beat the egg whites until stiff peaks form and set aside.
2. In a separate bowl, combine the sugar and orange zest, rubbing them together to release the zest's flavor.
3. Add the egg yolks and beat until creamy.
4. Add the orange juice and gently mix.
5. Pour in the oil and stir until well incorporated.
6. Sift the flour together with the baking powder and add to the mixture and stir until just combined.
7. Gently fold in the beaten egg whites.
8. Pour the batter into a greased and floured baking pan.
9. Bake in a preheated oven at 350°F (180°C) until a toothpick inserted into the center comes out clean (about 40 minutes).
10. Optionally, dust with sugar before serving.

Recipe & Photo Credit: fattoincasadabenedetta.it