How to Make It
Preheat oven to 300°.
Make the Crust: Place wafers in a food processor; pulse until ground. Drizzle crumbs with melted butter and oil; pulse until moist. With processor on, add egg white; process just until combined. Divide crumb mixture evenly among 12 muffin cups coated with cooking spray. Press evenly into bottoms and up sides of muffin cups. Bake at 300° for 15 minutes or until firm and just beginning to brown. Remove from oven; cool completely, about 10 to 15 minutes.
Make the Pudding: Combine milk, sugar, cornstarch, and salt in a small, heavy saucepan, stirring with a whisk. Cook over medium heat until thick and bubbly, stirring almost constantly. When milk mixture is thickened, place whole egg in a medium bowl. Add ¼ cup milk mixture to egg, stirring constantly with a whisk. Slowly add remaining milk mixture to egg, stirring constantly with a whisk. Return to saucepan; cook over medium heat 1 minute or until bubbly, stirring constantly. Remove from heat; add 1 tablespoon butter and vanilla, stirring until butter melts.
Assemble the Pudding Cups: Divide half of banana slices evenly among muffin cups; top evenly with pudding. Arrange remaining banana slices over pudding.