1. Preheat the oven to 160C/320F and prepare an ungreased 8-inch aluminum chiffon cake tin with a removable base
2. In a medium-sized bowl combine the orange juice, orange zest, egg yolks, vanilla extract, caster sugar (I), and vegetable oil, and whisk to combine
3. Sift in the flour and baking powder and whisk until just combined
4. Add the egg whites to the bowl of a stand mixer fitted with a whisk attachment and whisk until foamy, or add them to a large bowl and whisk with an electric mixer until foamy
5. Add the caster sugar (II) and whisk on medium speed until stiff peaks form
6. Add 1/3 of the meringue to the egg yolks and whisk until just combined
7. Transfer the lightened egg yolk mixture to the remaining egg whites and gently fold until just combined
8. Gently transfer the batter to the prepared cake tin and give the tin a few taps to remove any large air bubbles
9. Bake for 45 minutes, then reduce the oven temperature to 140C/285F and bake for 15 minutes or until an inserted skewer emerges clean
10. Remove from the oven and invert the cake onto a wire rack to cool completely
11. Once completely cooled run a thin knife around the sides and base of the cake to unmould
12. Slice and serve alone or with a dollop of whipped cream and fresh fruit

Whipped Cream

1. Combine the cream and sugar in the bowl of a stand mixer or large bowl and beat on medium speed until stiff peaks
2. Transfer the cream to a piping bag fitted with a large round tip

Assembly

1. Unmould the cooled cake
2. Top with cake with dollops of whipped cream and top with fresh slices of orange
3. Enjoy!