Preheat the oven to 175°C. Fit the pie dough into a 9-inch pie dish, fluting the edges, and chill until set, about 15 minutes. Prick the bottom and sides with a fork, and then line the crust with aluminum foil. Fill with pie weights or dried beans and bake until the edges of the crust are just golden, 20 minutes. Remove the foil with the pie weights and continue to bake until the bottom of the crust is dry and lightly browned, another 10 to 15 minutes. Cool completely.
Toss the rhubarb with a third of the sugar and the orange zest and juice until well combined. Transfer to the crust and spread to form an even layer. Place the pie on a rimmed baking sheet. Whisk the eggs with the cream, flour and remaining sugar until smooth, and then pour over the rhubarb. Bake until the pie is lightly browned, puffed and no longer wet in the center, about 1 hour 15 minutes. Cool completely on a wire rack. Before serving, lightly dust with icing sugar.
TIP: You can make this pie the day before and chill overnight in the fridge.