Place flour, Hermesetas Granulated and butter in a bowl. Rub the flour and the fat rapidly between the tips of your fingers into flakes. Turn in the curd cheese and blend quickly into a dough. Set aside for 30 minutes. Butter a flan ring (26-28 cm in diameter). Roll out the dough thinly and line flan ring. Prick bottom with a fork. Preheat the oven to 200ºC and bake the pastry shell for 20 minutes. Let cool. In a pan blend milk, Hermesetas Granulated, cornstarch and egg yolks. Over moderate heat and stirring continuously bring mixture to a boil. Remove pan from heat. Add lime juice and grated rind and stir well. Beat egg whites until stiff and fold carefully into mixture. Pour cream into pastry shell and spread even with a spatula. Chill for 1 hour.