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; 5 minutes or until thickened. Remove from heat; stir in vanilla.
Spread small amount on bottom of 1 and 1/2 quart casserole dish; cover with layer of nilla wafers. Top with layer of sliced bananas. Continue to layer wafers, bananas and custard to make 3 layers of each, ending with custard.
Now you can stop here and just add additional wafers to the top and enjoy or make a meringue to cover the top by beating the egg whites until stiff but not dry; gradually add remaining 1/4 cup sugar and beat until stiff peaks form. Cover top of pudding spread to cover entire surface. Bake at 350 degrees for 10-12 minutes or until slightly browned. Cool slightly and eat or refrigerate.
If you don't have much luck making meringue, reference my recipe for Never Fail Pie Meringue.
