First prepare the shortcrust pastry. Cut the butter (just taken out of the refrigerator and well chilled) into small pieces and rub into the flour with a pinch of salt so that it resembles breadcrumbs. Then add the sugar. Form a well and add the egg yolks, and knead lightly to form an elastic dough. Wrap in cling film and leave to rest in the refrigerator for at least 40 minutes. Blend the ricotta. Add the four egg yolks. Stir in the cinnamon, the grated lemon rind and the powdered vanilla essence.
Mix in the boiled wheat grain. Add the candied fruit. Beat the egg whites and sugar into stiff peaks and then fold them in gently. Press the shortcrust pastry into the baking tin. Add the filling. Bake the tart at 180°C for about an hour or until the top is golden brown. Finish by dusting with icing sugar.