Mix flour, salt, and sugar; add milk slowly.
Stir constantly over low heat until thickened.
Stir and cook for about 15 minutes.
Beat egg yolks in bowl and stir into mixture slowly stirring constantly.
Cook about 5 more minutes stirring constantly.
Remove from heat and add vanilla.
Line bottom of casserole dish with vanilla wafers, bananas (sliced) and custard mixture.
Repeat layers, ending with custard on top.
Beat egg whites until stiff.
Add 1/4 cup sugar; whip until it peaks.
Spread on top of custard and bake in oven at 450 degrees for about 5 minutes or until browned.
Remove from oven and serve
