Blend 1/2 cup of the sugar and the
cornstarch in a medium pot. Stir in milk.
Bring to a simmer, stirring often. Whisk
1 cup of the mixture into beaten egg yolks.
Stir egg mixture back into pot. Cook 4 to
5 minutes, until it reaches 160°, thickens and begins to bubble. Remove from heat;
stir in vanilla and butter. Cool completely.
In the bottom of each jar, place 3 vanilla
wafers. Cover with a layer of bananas.
Spoon a scant 1/4 cup of the pudding on
top of each. Repeat layering. Secure lids;
refrigerate at least 3 hours or overnight.
Just before serving, combine heavy
cream and remaining 1 tbsp sugar in a
bowl. Using a hand mixer, whisk until stiff
peaks form. Spoon over each dessert.