Preheat the oven to 180°C/ 360°F.
Butter and flour the bundt pan (Note 4).
Separate the eggs.
Beat the egg whites with an electric mixer until stiff.
Beat the egg yolks, sugar, and vanilla extract until pale and fluffy.
Slowly add the oil and continue beating until combined.
Add the orange juice and zest.
Add dry ingredients: Mix and sieve the flour, baking powder, and salt over the egg mixture. Fold in carefully.
Add the egg whites and carefully fold in as well.
Bake: Pour the mixture into the prepared dish and bake for 50 minutes. Make the skewer test: it should come out clean.
Rest: Let the cake in the pan for about 15 minutes, release it from the pan by gently going around the edges with a small butter knife, and then turn it onto a plate.
Dust: Let the cake cool completely and dust it with icing sugar or cover it with glaze just before serving (Notes 5 and 6).