I use store bought pie crust and this custard from epicurious, it fills 2 pies:
Filling
1/2 cup sugar
1/3 cup cornstarch
1/4 teaspoon salt
1 3/4 cups whipping cream
1 1/4 cups milk
3 large egg yolks
2 tablespoons (1/4 stick) unsalted butter
3 teaspoon vanilla extract
5 ripe bananas (about 1 1/2 pounds total), peeled, cut crosswise into 1/4-inch-thick slices
Whisk sugar, cornstarch, and salt in heavy medium saucepan to blend. Gradually whisk in whipping cream and milk, then egg yolks. Whisk over medium-high heat until custard thickens and boils, about 6 minutes. Remove from heat. Whisk in unsalted butter and vanilla extract. Transfer custard to large bowl; cool completely, whisking occasionally, about 1 hour.
Stir custard to loosen, if necessary. Spread 1 cup custard over bottom of prepared crust. Top with half of sliced bananas, then 1 cup custard, covering bananas completely. Repeat layering with remaining bananas and remaining custard. Chill banana cream pie until filling is set and crust softens slightly, at least 8 hours and up to 1 day. Cut pie into wedges and serve.
