This is my adaptation of a recipe from Sarabeth Levine, of Sarabeth's. If you've never made a 'from-scratch' cream pie, it's not difficult at all, and so worth it for great flavour. Make sure you make the almond crust - like a yummy cookie!
For crust: Cream butter and sugar in processor until smooth and fluffy; add egg and blend until smooth; add flour, 2/3s cup of almonds (retaining 1/3 cup for topping), baking powder and salt and process just until combined; gather dough into ball; flatten into disk.
Wrap in plastic and refrigerate 1 hour.
Press dough into 9-inch diameter glass pie dish, trimming excess even with edge of dish; crimp edge decoratively; refrigerate 1 hour.
Preheat oven to 350°F; line crust with foil; fill with dried beans or pie weights; bake 12 minutes; remove beans and foil and bake until crust is set and edges are golden-brown, about 20 minutes; transfer to rack and cool.
For filling: Pour 2 tbs water into small bowl; sprinkle gelatin over; let stand 10 minutes to soften; pour milk into medium saucepan; scrape seeds from vanilla bean into milk; add bean; bring to simmer; whisk yolks, 1/3 cup sugar and cornstarch in medium bowl until thick; gradually whisk in hot milk; return mixture to same saucepan and cook over medium heat until mixture just begins to boil and thicken, whisking constantly, about 3 minutes; add softened gelatin and stir to dissolve; press plastic wrap directly onto surface of pastry cream and chill until cool, about 30 minutes.
Beat cream, confectioners’ sugar and 1/2 tsp vanilla extract in large bowl to stiff peaks; carefully fold 1 ½ cups whipped cream into pastry cream; fold in bananas; spoon mixture into pie crust; spoon remaining whipped cream into pastry bag fitted with medium star tip; pipe whipped cream over filling, covering completely; chill until set, at least 3 hours and up to 6 hours; just before serving, sprinkle with remaining 1/3 cup of toasted almonds.
Note: Because of the bananas, this pie is best eaten the day of making as they do turn brown as time passes - the flavour's still great, though.