To make the pastry, tip the flour into a large bowl and add a pinch of salt. Add the butter and use a round-bladed knife to cut the butter into the flour, repeating the process until the pieces are half their original size. Use your fingertips to continue rubbing in until there are only small flecks of butter visible. Add the brown sugar and mix to combine.

Make a well in the middle of the mixture, then add the egg yolks, ice-cold water and lemon juice and mix using the knife until the dough starts to clump together. Use your hands to gather the dough into a ball and very gently knead for 20 seconds until smooth. Flatten into a disc, wrap and place in the fridge for at least 2 hours.

Put the dough on a lightly floured work surface, cut off one-quarter and set aside. Roll out the remaining dough to 2–3mm/⅛in thick and use to line the pie tin. Trim off any excess pastry with a sharp knife, then prick the base with a fork and chill for 20 minutes.

Preheat the oven to 180C/160C Fan. Roll out the reserved dough to 2–3mm/⅛in thick. Cut or stamp out decorative leaf shapes and chill until needed.

Line the pastry case with foil and fill with baking beans (or uncooked rice or pulses) and bake for about 20 minutes, until starting to turn golden at the edges. Remove the foil and beans and cook for about 4 minutes more to dry out the base.

While the pastry is baking, prepare the filling. In a large bowl, combine all the ingredients and whisk until smooth.

Brush the underside of each pastry leaf shape with a little water and arrange around the edge of the pastry case. Brush the top of the leaves with a little milk and sprinkle with caster sugar. Carefully pour the pumpkin mixture into the pastry case and return to the oven for 25–30 minutes, until the filling is just set with a slight wobble in the middle.

Leave the pie to cool at room temperature before slicing. Serve with whipped cream.