Line the bottom and sides of a 2 1/2 quart glass bowl with about 40 vanilla wafers.
Combine sugar, cornstarch, and salt in a medium saucepan. Gradually whisk in evaporated milk, until sugar and cornstarch begin to dissolve.
Whisk in eggs and add butter. Cook over medium heat, stirring constantly, until the mixture begins to thicken. Reduce heat to low, simmer and cook for 1 minute, stirring constantly.
Remove from the heat. Stir in vanilla extract. Let cool slightly.
Pour half of the pudding over the wafers. Top with half of the bananas. Layer remaining vanilla wafers over bananas. Combine remaining pudding and bananas then spoon over wafers.
Refrigerate for at least 4 hours. Top with whipped cream.
Cook's Note: Here we've displayed the pudding in ramekins.