Preheat the oven to 340F.
In a large mixing bowl whisk together flour and cornstarch. Add mashed banana, oil and vanilla extract. Whisk until smooth.
Put brown and granulated sugar in one bowl. Place the egg whites in a mixer bowl.
Beat the egg whites on low speed until foamy. Then, add the sugar in 3 batches. Beat on medium or medium high until stiff peaks form.
With a spatula, fold in the meringue into the banana mixture in 3-4 batches.
Pour the batter into ungreased 10" tube pan with removable bottom and legs. Bake about 45 to 60 minutes or until the top slightly springs back when you press it and a toothpick inserted in the top comes out clean.
Invert pan onto legs and cool at least an hour before reinverting pan.
Then, carefully run a knife around the edge of the pan just to release the cake and turn onto cake plate. Remove the top in the same way.
