1 cup whole milk
4 egg yolks
1 cup granulated sugar
5 tablespoons all-purpose flour
3 tablespoons butter, cut in small pieces
1/2 teaspoon ground cinnamon
1 1/2 teaspoon vanilla extract
2 cups heavy cream divided
2 bananas, thinly sliced and tossed with 1 1/2 tablespoons lemon juice (about 1/2 lemon)
1 baked 9-inch pie shell
In a heavy saucepan, bring milk to the boiling point.
Place egg yolks in mixing bowl and beat on medium speed of electric mixer, gradually adding sugar. Beat for 2 minutes, until mixture is thick and lemon-colored. Beat in flour. With mixer on low speed, gradually add the hot milk.
Transfer mixture to heavy saucepan and heat over medium heat, stirring constantly. Let mixture come to a boil and boil for about 1 minute, stirring constantly. Remove from heat and continue to beat until mixture is smooth. Beat in butter a little at a time; then blend in cinnamon. Stir in vanilla extract; let mixture cool.
Beat 1 cup of the cream until firm but not stiff. Mix about 1/2 cup of the whipped cream into the egg mixture to lighten it. Fold remaining whipped cream into egg mixture then fold in sliced bananas.
Transfer filling to the pastry shell. Whip remaining cream and spoon or pipe onto the pie. Refrigerate until serving time.