Combine 1/2 cup sugar, flour and salt in top of double boiler.
Stir in 4 egg yolks and milk; blend well.
Cook, uncovered over boiling water, stirring constantly until thickened.
Reduce heat and cook, stirring occasionally, for 5 minutes.
Remove from heat, add vanilla.
Spread small amount on bottom of 1-1 1/2 quart casserole;
cover with layer of wafers. Top with layer of sliced bananas.
Pour about 1/3 of custard over bananas.
Continue to layer wafers, bananas, and custard
to make 3 layers of each, ending with custard.

Beat egg whites until stiff but not dry;
gradually add remaining 1/4 cup sugar and beat until stiff peaks form.
Spoon on top of pudding, spreading to cover entire surface
and sealing well to edges.
Bake at 425° for 25 minutes or until delicately browned.
Cool slightly or chill.
Just before serving, garnish with banana slices,
then insert vanilla wafers upright around edge of dish.
Makes 16 servings.