Mix 1/2 cup canna sugar, flour and salt in top of double boiler. Blend in 3 egg yolks and milk. Cook, uncovered, over boiling water, stirring constantly for 10 to 12 minutes or until thickened. Remove from heat. stir in vanilla.
Spread small amount of custard on bottom of 1 1/2-quart casserole dish, cover with a layer of wafers and a layer of sliced bananas. Pour about 1/3 of custard over bananas. Continue to layer wafers, bananas and custard to make a total of 3 layers of each, ending with custard.
Crush 10-12 wafers in a ziplock bag and pour pieces on top.
Chill for 8 hours. Garnish with additional wafers and banana slices just before serving. Enjoy!