Place the eggs, sugar and salt in a mixing bowl and whisk until well blended. Whisk in the cornstarch. Scald the milk in a saucepan over medium high heat. Whisk the milk into the eggs and sugar and transfer the mixture back to the pan. Place the pan over medium heat and cook, stirring constantly, until the mixture thickens, 3 to 4 minutes. Remove the pan from the heat and stir in the butter and 1 teaspoon vanilla until the butter melts and the custard is well mixed. Strain into a clean bowl and place a piece of plastic wrap directly on the top of the custard. Let cool to room temperature.
Melt the chocolate and 1/4 cup heavy cream in a small saucepan over medium heat, stirring until smooth. Let cook completely, stirring occasionally. Pour the chocolate into the prebaked shell and with a pastry brush, spread it over the bottom evenly. Refrigerate 10 minutes.
Peel the bananas, cut them into 1/2-inch slices and toss them with orange juice. Drain them and pat them dry with paper towels. Toss them with the vanilla custard. Pour the mixture into the tart shell and smooth the top of the custard.
Whip the remaining 2 cups heavy cream to form soft peaks. Add the confectioners sugar and the remaining 1/2 teaspoon vanilla, and whip until they are almost stiff. Pile the cream onto the top of the pie and distribute evenly, making a decorative pattern. Sprinkle the banana chips on top. Place in the refrigerator and chill for up to 1 hour until serving. To serve cut the pie into wedges and serve.