Blind bake one half of pie dough and let cool.

Prepare an ice bath; set aside. In a bowl, lightly whisk egg yolks; set aside. In a saucepan, whisk together milk, granulated sugar, cornstarch, and salt. Bring to a simmer (do not boil), and cook, whisking constantly, 3 to 4 minutes.

Whisk a quarter of hot-milk mixture into egg yolks; whisk in remaining milk mixture. Strain into a clean saucepan, and cook over medium-high heat, whisking constantly, until custard is thick and bubbles appear in center, 2 to 3 minutes. Transfer to a medium bowl, cover with plastic wrap, pressing directly onto surface to prevent a skin from forming. Set in ice bath until completely chilled, 30 to 35 minutes. (Filling can be kept in refrigerator, covered with plastic wrap, up to 1 day.)

Cut 3 or 4 bananas into ¼-inch slices, slightly on the bias. Arrange slices in slightly overlapping rows at bottom of crsut. Cover with custard, using an offset spatula to create an even layer. In the bowl of an electric mixer fitted with the whisk attachment, combine cream and confectioners' sugar; beat until soft peaks form. Spread the whipped cream on top of the custard. Refrigerate pie, loosely covered with plastic wrap, for at least 1 hour or up to 2 days.

Just before serving, cut 3 or 4 bananas into ¼-inch slices, slightly on the bias. Beginning at the edge of the piecrust, arrange the slices in slightly overlapping rows on top of the whipped cream.