Bake the crust. Blind bake your 9-inch crust according to package or recipe instructions. It should be golden and fully set. Cool completely. A warm crust + custard = soggy regret.
Make the custard base. In a medium saucepan, whisk together sugar, cornstarch, and salt. Add milk gradually, whisking until smooth. In a separate bowl, whisk the egg yolks.
Temper the yolks. Heat the milk mixture over medium, whisking constantly, until it begins to steam and thicken slightly. Slowly drizzle about 1/2 cup of the hot milk into the yolks while whisking. Then pour the yolk mixture back into the pan.
Thicken the custard. Continue cooking over medium heat, whisking nonstop, until it reaches a thick, pudding-like consistency and bubbles lazily—about 2–4 minutes. Remove from heat and whisk in butter and vanilla. The custard should coat a spoon and hold a line when you drag a finger through it.
Cool it fast. Transfer custard to a bowl. Press plastic wrap directly on the surface to prevent a skin. Let it cool until just warm, not hot—about 20–30 minutes. FYI: Hot custard will steam the bananas and make them limp.
Slice the bananas. Cut into 1/4-inch rounds. If you’re worried about browning, gently toss with lemon juice. Don’t soak them—just a whisper.
Layer the pie. Arrange a snug layer of banana slices over the cooled crust. Spoon half the custard on top and smooth. Add a second layer of banana slices, then the remaining custard. Smooth the surface. You’re building flavor strata like a dessert geologist.
Chill to set. Cover and refrigerate at least 4 hours (overnight is peak). This is where the magic—and the clean slices—happen.
Whip the cream. Beat the cold cream, powdered sugar, and vanilla until medium-stiff peaks form. Think “holds shape,” not “butter.”
Finish and serve. Top the chilled pie with whipped cream. Garnish with toasted coconut, chocolate shavings, or crushed wafers if you’re feeling extra. Slice with a sharp knife, wiped clean between cuts.