Preheat oven to 350°F (175°C). In a medium bowl, combine 1.5 cups graham cracker crumbs, 2 tbsp granulated sugar, and 1/4 tsp fine salt. Melt 6 tbsp unsalted butter and pour over crumbs. Stir until evenly moistened and texture holds when pressed. Press mixture firmly and evenly into a 9-inch (23 cm) pie dish, covering bottom and sides to form an even crust (use the bottom of a measuring cup for firm pressing). Bake in preheated oven 10 minutes until set and beginning to brown at edges. Remove and cool on a rack while preparing filling. Reduce oven to 325°F (160°C) if your recipe timing calls for it (pastry cream is cooked on stovetop so oven reduction optional).

Pastry Cream (Filling)

Warm Dairy

In a medium saucepan, combine 2 1/2 cups whole milk and 1/2 cup heavy cream. Warm over medium heat until steam appears and small bubbles form at the edge (do not boil). Stir occasionally to prevent skin from forming.

Whisk Eggs & Dry Ingredients

While milk warms, whisk together 3/4 cup granulated sugar and 1/3 cup cornstarch in a medium bowl. Add 4 egg yolks and 1 whole egg and whisk until smooth and pale. This mixture should be lump-free.

Temper Eggs

Slowly pour about 1/2 cup of the hot milk mixture into the egg mixture in a thin stream, whisking constantly to raise the eggs' temperature. Repeat with another 1/2 cup if necessary until the egg mixture is warm (this prevents curdling).

Cook Pastry Cream

Return the tempered egg mixture to the saucepan with the remaining warm milk. Place over medium-low heat and cook, whisking constantly, until the mixture thickens and comes to a gentle boil (about 2–4 minutes once thick). Continue cooking and whisking for 1 minute after boiling to fully activate cornstarch and remove the raw starch taste. The pastry cream should be thick enough to coat the back of a spoon.

Finish & Chill

Remove saucepan from heat. Stir in 3 tbsp unsalted butter, 2 tsp vanilla extract, and 1/8 tsp fine salt until butter melts and mixture is smooth. Pour the hot pastry cream into a shallow bowl and press a piece of plastic wrap directly on the surface to prevent a skin from forming. Chill until cool, at least 2 hours (or speed chill in refrigerator for 45–60 minutes if covered directly).

Bananas & Assembly

Prepare Bananas

Slice 3 ripe but firm bananas into 1/4-inch rounds. Toss the banana slices gently with 1 tsp lemon juice to prevent browning.

Assemble Pie

Once the crust is cooled and the pastry cream is fully chilled and set, spread a thin layer of pastry cream on the bottom of the crust to anchor banana slices. Arrange a single layer of banana slices over the base cream. Spoon or pipe about two-thirds of the pastry cream over the banana layer and smooth evenly. Arrange another layer of banana slices on top of the cream if desired, then spread remaining pastry cream to cover. Smooth the top with an offset spatula. Cover the pie loosely with plastic wrap and chill at least 2 hours to let flavors meld and filling fully firm up.

Top with Whipped Cream

Before serving, whip 1 1/2 cups lightly sweetened whipped cream (or use prepared topping) with 1 tbsp powdered sugar until soft peaks form if making fresh. Spread or pipe the whipped cream over the chilled pie, covering the filling entirely. Garnish with 2 tbsp grated dark chocolate or chocolate shavings and additional banana slices if desired. Serve chilled.