To make the filling: In a heatproof bowl, whisk together the egg yolks, sugar, cornstarch, and salt until thick and pale in color. Set aside.
In a medium saucepan, heat the half-and-half to just below a boil. Whisk about 1 cup of the hot half-and-half into the egg yolk mixture to temper the yolks, so they won’t curdle, then, continuing to whisk, add the remainder of the half-and-half in a steady stream.
Set the bowl over a saucepan of simmering water (do not let the bottom of the bowl touch the water) and cook, whisking constantly, until thickened, 5 to 7 minutes.
Remove the bowl from the heat and whisk in the vanilla and banana liqueur or extract until well combined. Let the filling mixture sit for 2 to 3 minutes to cool slightly, then whisk in the butter until the custard is smooth and silky. Place a piece of plastic wrap directly on top of the custard so that a skin does not form and let cool for 30 minutes, or until it reaches room temperature.
When the filling has cooled, pour half of it into the prepared pie crust. Add a layer of the sliced bananas, followed by the rest of the filling. Cover with plastic wrap and place it in the refrigerator to chill for at least 3 hours, or overnight.
Nilla Wafer Pie Crust
2 Tbsp unbleached all-purpose flour
2 Tbsp pinch of fine sea salt
8 Tbsp unsalted butter, at room temperature
To make the crust: Position a rack in the lower third of the oven and preheat the oven to 350°F.
Put the cookies in a zip-top plastic bag and pound them with a rolling pin until they become coarse crumbs. Alternatively, pulse the cookies in a food processor. You should have 2 cups.
In the bowl of a stand mixer fitted with the paddle attachment (or in a large mixing bowl, using a handheld mixer), mix the cookie crumbs, flour, sugar, salt, and butter on low speed until the crumbs and flour are evenly moistened, 3 to 5 minutes. You may be tempted to add more butter--don’t.
Press the dough evenly over the bottom and up the sides of a 9-inch pie dish. Bake for 6 to 8 minutes, until golden brown. Let cool completely before filling.
Fresh Whipped Cream
¼ cup confectioners' sugar
To make the fresh whipped cream: Using a stand mixer fitted with the whisk attachment (or in a large mixing bowl--using a handheld mixer), whip the cream on medium speed until it starts to thicken. Add the confectioners’ sugar and beat until the cream holds nice soft peaks.
Pile the whipped cream on top of the pie with a spatula. Sprinkle with grated nutmeg and decorate with vanilla wafers and banana slices. The pie is best served the same day, but it can be covered and refrigerated for up to 3 days.
Tip: Here is a great way to prevent bananas from turning brown in your pie. Using a pastry brush. Brush them with lemon or orange juice. Other liquids you can use are lime juice, pineapple juice, orange soda, or lemon-lime soda.
Excerpted from The Back in the Day Bakery Cookbook by Cheryl Day & Griffith Day/Artisan Books, 2012.