Step 1

Whisk together egg yolks and cornstarch in a medium-size heatproof bowl until well combined. Whisk together milk, whipping cream, sugar, nutmeg, and salt in a medium saucepan. Cook over medium, whisking often, until steaming, about 4 to 6 minutes (do not let milk mixture boil). Remove from heat. Using a ladle, slowly drizzle 1 cup steaming milk mixture into egg mixture, whisking constantly until combined. Slowly drizzle egg mixture into remaining warmed milk mixture in saucepan, stirring constantly until combined. Cook milk mixture over medium, whisking constantly until mixture thickens and begins to simmer (about 200°F), about 8 to 10 minutes. Remove saucepan from heat, and whisk in butter and vanilla. Transfer pudding to a medium bowl; cover with plastic wrap, pressing wrap directly on surface to prevent a skin from forming. Refrigerate until completely chilled, about 3 hours.

Step 2

Spoon 3 tablespoons crushed vanilla wafers into each of 12 stemless wineglasses or other 8-oz. glasses; top each with about ⅓ of a sliced banana and ⅓ cup pudding. Dollop each with about 2 tablespoons Vanilla Bean Whipped Cream, and sprinkle with 1 teaspoon crushed vanilla wafers. Cover loosely, and chill for at least 1 hour (or up to 4 hours) before serving. Garnish each glass with a whole vanilla wafer, if desired.