1. Preheat the oven to 400°F (200°C). Line a 9in (23cm) pie dish with the pie dough. Prick the dough all over with a fork.

2. Line the dough with wax paper, then fill with baking beans. Place the pie dish on a baking sheet. Bake for 10 minutes or until the pastry looks set. Remove the paper and beans and prick the dough again. Bake for about 10 minutes more, until the pastry is golden brown. Transfer to a wire rack and let cool.

3. Meanwhile, beat the egg yolks, sugar, cornstarch, and salt together well in a medium saucepan until the mixture is pale yellow. Whisk in the hot milk and vanilla. Cook over medium heat, stirring constantly, just until thickened and beginning to boil. Reduce the heat to low and let cook and bubble gently, stirring, for 2 minutes more. Strain through a wire sieve into a bowl, press a piece of plastic wrap on the surface, and let cool.

4. Thinly slice the bananas and toss with the lemon juice. Spread them in the pie shell, then top with the custard. Cover with plastic wrap and refrigerate until chilled, at least 2 hours.

5. Beat the cream and confectioner's sugar until stiff peaks form. Spread over the filling and serve chilled.