This creamy banana dessert is our very favorite version, piled high with layers of just-ripe bananas, rich vanilla pudding and tender cookies. We used vanilla bean paste instead of extract in our homemade filling for a bold flavor boost and topped the pudding with swirls of freshly whipped cream. When it all comes together, it's dreamy, luscious and feeds a crowd!
Bring the milk to a simmer in a large saucepan over medium heat, then remove from the heat. Meanwhile, whisk the sugar, cornstarch, egg yolks, vanilla paste and salt together in a medium bowl.
While whisking, slowly add about 1 cup of the warm milk to the egg mixture. Pour the egg mixture back into the saucepan, whisking constantly. Continue to cook over medium heat, whisking constantly, until the mixture comes to a boil. Lower the heat to maintain a simmer and cook until thickened, 3 to 5 minutes. Remove from the heat and whisk in the butter.
Transfer the pudding to a large bowl and press a piece of plastic wrap directly against the surface. Refrigerate until cold, about 1 hour.
Arrange 19 wafer cookies in the bottom of a 4-quart trifle dish. Top with 1 cup pudding, then arrange 2 sliced bananas on top. Repeat the layers ending with bananas.
Add the heavy cream, confectioners' sugar and a pinch of salt to the bowl of a stand mixer fitted with a whisk attachment. Beat on medium-high speed until stiff peaks form, about 2 minutes.
Spread the whipped cream over the pudding and sprinkle the crushed wafer cookies around the border. Refrigerate until the pudding is firm, at least 2 hours or up to overnight.