Make the shortcrust pastry and leave it to rest in the refrigerator.
Preheat the oven to 360F/180C/gas 4. Line an 8” tin with pastry and bake it blind for 15-20 minutes until it is just golden. The tart should be 3/4 cooked. Remove beans, paint base with a little egg white and replace in oven for 2-3 minutes. When it is cooked, let it cool while the filling is prepared. Lower the oven temperature to 150C/300F/gas 3.
Whisk all the ingredients for the tart filling together - the eggs, orange and lemon juice, lemon zest, cream and sugar.