Rub cold butter through flour and salt until small flakes remain, then add cold water gradually and mix just enough to form a soft pastry.
Flatten the pastry, wrap tightly, and refrigerate for thirty minutes while you drain ricotta and prepare the sweet, lightly citrus scented filling in a separate bowl.
Beat ricotta with granulated sugar, egg, vanilla, lemon zest, and finely chopped candied orange peel until smooth, avoiding excessive beating that makes the filling loose.
Roll pastry into a large circle and fit a twenty-three centimeter tart pan, pressing the edges gently without stretching the dough across the base underneath.
Spoon the ricotta filling evenly into the chilled pastry shell and level the surface, leaving a small gap below the rim for expansion during baking.
Bake at 180 degrees Celsius for forty to forty-five minutes until the crust is golden and the center barely trembles, then cool fully before slicing.
