2) Drizzle in half of the iced water and rake through mixture with fingers until just moistened. Drizzle in the remaining water 1 tablespoon at a time and comb through mixture with fingers to moisten. It will go from being a shaggy mess to a smooth dough and will be moist enough when it is moistened through, but not wet when pressed. (Do not overwork the dough or it will become tough.)
3) While rotating the bowl with 1 hand, push dough between other palm and side of bowl to gather into a ball. Turn the dough onto a piece of clingfilm, press it into a flat disc and seal the clingfilm. Place the pastry in the coldest part of refrigerator (usually back bottom shelf) for at least 30 minutes.
4) Remove from the fridge and before roll out to form a crust.
To make the coffee whipped cream:
1) Place a glass or metal bowl and metal whisk in the freezer for about 5 minutes, until cold.
2) When everything is cold, pour the cream into the bowl and begin to whisk for about 1 minute, until it froths up and starts to thicken. Whisk vigorously for about 1 minute, until soft peaks form (the cream will hold a point when the whisk is lifted but will fall back into the bowl almost immediately).
3) Add the liqueur and whisk for about 1 minute, until stiff peaks just form (the cream stays put on the whisk when it is lifted from the bowl).
4) Cover and place in the refrigerator until ready to use.
To bake the crust:
1) Place a baking sheet on an oven shelf above the centre of the oven and preheat the oven to 190C/Gas 5.
2) Meanwhile, roll the dough on a lightly floured surface into a 30cm diameter circle approximately 6mm thick.
3) Transfer the dough to a 24 cm pie dish and trim the edges so that there is a 12mm overhang. Use the excess dough to press the crust into the pie dish. Fold the edge of crust back on itself and press, as desired, into a decorative crust. (Can be made 2 days ahead and kept covered in refrigerator until ready to use.
4) Pierce the bottom of the crust all over with a fork, line the pastry with aluminium foil so it overhangs slightly and covers the edges of the crust and fill with uncooked rice, dried beans or ceramic baking beans. Place the pie dish on the preheated baking sheet and bake blind for about 25 minutes, until the pastry is set and the edges are slightly puffed up.
5) Gather the foil together and remove along with rice or beans. Continue to bake the pastry for about 15 minutes, until it is golden.
6) Place the pastry case on a wire rack and allow to cool for a few minutes before filling.
Whilst the pastry is baking, prepare the filling:
1) Peel a banana and place it in a blender together with the milk, egg yolks, cornflour, sugar, vanilla, and salt. Blend until smooth and pour into a small saucepan.
2) Bring to a simmer over medium heat and cook, stirring constantly for about 7 to 8 minutes, until the mixture bubbles into a thick custard.
3) Remove from the heat and stir in the butter, a few pieces at a time, until melted. Set aside to cool slightly.
1) Pour the banana filling into the pastry case and smooth with a spatula.
2) Slice the remaining 3 bananas into 1cm pieces and arrange on top of the custard filling.
3) Smooth the coffee whipped cream over the top of the bananas, loosely cover in plastic, and place in the refrigerator for at least 3 hours until it has set.