Preheat the oven to 220°C.
Mix together the butter and the flour, rubbing together with your fingertips. Once you have a rough crumble, add the sugar and the egg yolks. Combine all the ingredients but be careful not to overwork the pastry.
Press the pastry out into a flat 5mm thick disc on a sheet of baking parchment. Cover with a second sheet of baking parchment and then chill in the fridge for 30 minutes.
Cut the pastry into discs slightly larger than your individual tartlet tins. Line the tins with the pastry, lightly pressing the pastry down at the edges. Cover the pastry with baking parchment and then add the baking beans. Blind bake for 15 minutes and then allow to cool.
Juice the oranges and the lemon. Place the sugar and the citrus juice in a saucepan and heat to melt the sugar. Then remove from the heat and allow to cool a little.
Beat the whole eggs and then add the corn starch. Add this mixture to the citrus juice, bring back to the boil and beat until thick. Pour the orange cream into the pastry cases and then chill in the fridge to set.
Decorate each tartlet with some segments or a slice of orange to serve.
«Make sure that the pastry is very well chilled before placing in the oven to cook.»