2Sift flour, 1/2 of the sugar, baking powder, and salt together in a bowl. Add egg yolks, water, oil, and vanilla extract and beat until smooth.
3Beat egg whites and cream of tartar together in a bowl using an electric mixer until soft peaks form. Continue beating until stiff and shiny peaks form; add remaining sugar and beat until incorporated. Fold egg yolk mixture and bananas into egg white mixture just until blended. Slowly pour batter into a 10-inch tube pan.
4Bake in the preheated oven until cake springs back when lightly touched, 55 to 65 minutes. Invert pan onto a plate and cool. Loosen edges of cake and remove pan.
Footnotes
Cook's Notes:
Use very ripe bananas for best taste. After mashing bananas, use immediately or the bananas will brown and color the cake.
Use 1 cup sugar instead of 1 1/4 cups for a lighter taste.