Preheat oven to 190 C / Gas 5. Wash tube cake tin in hot soapy water to ensure it is totally clean. Let dry completely. Sieve flour, cornflour and 90g icing sugar together three times; set aside.
In mixing bowl, beat egg whites and salt on high speed until foamy. Add cream of tartar, 1 teaspoon vanilla and almond extract; beat until soft peaks form. Peaks should be soft enough so they bend over slightly at the tips. Gradually add 200g caster sugar, continuing to beat until stiff peaks form. Sieve about 1/4 of the flour mixture over the egg whites and using flat spatula, quickly but gently fold into egg whites. Repeat using 1/4 of the flour mixture each time. Pour batter into clean tube cake tin. Gently cut through batter with knife to remove air pockets.
Bake for about 30 to 35 minutes or until an inserted skewer comes out clean. Invert tin onto a wire rack to cool for 1 hour.
Beat 240g icing sugar, butter, cream and 1 teaspoon vanilla together until smooth. Add more cream or icing sugar as needed. Ice the cooled cake.