In a mixing bowl, combine caster sugar, vegetable oil, orange juice, and orange extract, whisking until smooth.

Sift in the cake flour and mix gently until a velvety batter forms.

In a separate bowl, whip egg whites until soft peaks form. Gradually add cream of tartar and remaining caster sugar, beating until stiff peaks form.

Gently fold the meringue into the cake batter with a rubber spatula.

Pour the batter into a non-greased chiffon tube pan and smooth the top.

Bake in a preheated oven at 350°F (175°C) for approximately 35 minutes until a toothpick comes out clean.

Cool the cake upside down for at least 1 hour.

Whip double cream until it thickens, then add icing sugar and whip until soft peaks form.

Frost the cooled cake with the orange whipped cream and decorate as desired.