Banana Cream Pie

Banana cream pie is part of the American 'cream pie' tradition of stirred custards in a baked shell that flourished from the late 19th century onward. Bananas were a novelty in the United States until refrigerated steamship and rail transport in the 1870s–1900s made them cheap and ubiquitous; once common, they were folded into the existing custard-pie repertoire, much as they were into banana pudding and banana split in the same era. The pie has no single documented inventor and is a folk-and-commercial standard; in 1951 the U.S. Army reportedly named banana cream the favourite pie of American servicemen, a frequently repeated marker of its mid-century popularity.

Cool and yielding, the pie offers almost no resistance — soft custard, soft banana, soft cream. The pastry cream is silky and richly vanilla, the banana slices slick and sweet, gone faintly fragrant and winey from ripening. The whipped-cream top is light and just sweet. Underneath it all the crust should still snap, a single crisp note against the softness. The banana flavour reads stronger after a few hours' chilling, when it has perfumed the surrounding cream.

The filling is a vanilla pastry cream — milk thickened with egg yolks and starch, cooked to about 80–85°C so the starch gelatinizes and yolk proteins set into a glossy, pipeable cream that the starch keeps from curdling. Bananas brown when cut because an enzyme (polyphenol oxidase) reacts with oxygen; tossing the slices with a little lemon juice or sealing them under warm custard slows this. Ripe bananas taste sweeter and more aromatic because their starch has converted to sugar and they have developed fruity ester compounds. The whipped-cream top is a foam of cold cream beaten until its fat traps air; it must stay cold or it weeps and deflates.