Warm the Pudding Base: In a medium saucepan, combine 2 cups of half and half, the seeds from 1 vanilla bean, and a pinch of freshly grated nutmeg. Heat until it begins to shimmer, stirring occasionally.

Whisk Egg Mixture: In a separate bowl, whisk together 3/4 cup of granulated sugar, 1/4 cup of cornstarch, 1/4 teaspoon of salt, and 4 egg yolks until light and fluffy, about 2 minutes.

Combine Mixtures: Gradually pour the hot half and half mixture into the egg mixture, whisking constantly. Return to the saucepan and heat, whisking continuously, until it thickens, about 5–7 minutes.

Cook Until Thickened: Continue to cook for an additional minute after boiling, stirring constantly. Remove from heat and stir in 2 tablespoons of unsalted butter and 1 teaspoon of vanilla extract.

Chill Pudding: Transfer pudding to a bowl and cover with plastic wrap pressed directly on the surface. Chill in refrigerator for at least 2 hours.

Layer Pudding: In a large baking dish, layer vanilla wafer cookies, half of the chilled pudding, sliced bananas brushed with lemon juice, and top with remaining pudding. Chill for another 2 hours.

Make Topping: In a clean mixing bowl, whip 1 cup of heavy cream with 2 tablespoons of sugar and 1 teaspoon of vanilla extract until stiff peaks form, about 3-5 minutes.

Garnish and Serve: Sprinkle crushed vanilla wafers over whipped topping and add banana slices as garnish. Serve chilled.