In a large mixing bowl, combine 1 cup of caster sugar, ½ cup of vegetable oil, ¾ cup of fresh orange juice, and 1 ½ cups of cake flour. Mix until the batter is smooth and well blended, about 2 minutes.

In a separate, grease-free bowl, add 6 egg whites and whip with an electric mixer on high speed until stiff peaks form, about 4 to 6 minutes.

Gently fold the whipped egg whites into the cake batter using a rubber spatula.

Pour the batter into an ungreased 10-inch tube pan and bake in a preheated oven at 325°F (160°C) for about 35 minutes.

Once baked, remove the cake from the oven and immediately invert the tube pan. Allow the cake to cool completely upside down for about 1 hour.

In a clean mixing bowl, whip 1 cup of double cream and add 2 tablespoons of icing sugar until soft peaks form, about 3 to 5 minutes.

Carefully remove the cake from the tube pan and frost the top with the zesty orange whipped cream right before serving.