In a heavy-bottomed pot, heat sugar, cornstarch, flour, salt, and milk over medium heat. Bring to a slow rolling boil and let thicken. Continue to cook and stir until the mixture coats the back of a spoon.

While the milk mixture is cooking, place egg yolks in small bowl. Temper egg yolks by spooning a small amount of hot milk into a bowl. Keep stirring.

Bring it back to a boil for 1 minute.

Remove from heat and add butter and vanilla.

Let chill in refrigerator and cool completely.

Beat whipping cream until soft peaks form. Add powdered sugar. Stir in vanilla.

Slice bananas and sprinkle with lemon juice or fruit fresh to prevent browning.

Layer banana pudding dessert with pudding, bananas, nilla wafers, and whipped cream.

Let chill in refrigerator to set up.