Step 1 Prepare the vanilla pudding. In a medium saucepan, whisk together the sugar and cornstarch. Gradually add the milk and cook over medium heat until thickened. Remove from heat. Step 2Add about 1/3 of the milk mixture into the egg yolks and whisk until well combined. Add this mixture back to the saucepan. Bring to a boil whisking constantly. Cook for 2 minutes. Remove from heat and add butter, vanilla, and salt. Mix until smooth. Strain into a bowl. Cover with plastic wrap making sure it touches the surface of the pudding so it does not form a skin. Refrigerate for about one hour.Step 3In a large bowl, beat together the cream and powdered sugar at medium speed. When the cream starts to thicken, increase the speed to medium high and beat until soft peaks are formed. Do not over whip. Step 4Using a trifle dish or a large bowl, assemble the pudding by layering vanilla pudding, whipped cream, cookies, and bananas. End the layering with whipped cream. Cover and refrigerate for 2 hours. Garnish with crumbled cookies before serving.