Preheat your oven to 375°F.
Lightly butter a 9-inch glass pie dish, ensuring that the entire surface is coated well.
Blend powdered sugar, eggs, vanilla extract, orange zest, and ricotta cheese in a food processor.
Mix until smooth, and ensure no lumps remain.
Incorporate the cooked short-grain rice and pine nuts into the smooth mixture.
Stir gently until everything is just combined.
Lay one phyllo sheet over the bottom and up the sides of the pie dish.
Brush it with melted butter, letting the phyllo hang over the sides of the dish.
Continue layering the remaining phyllo sheets, brushing each with melted butter before adding the next.
Pour the ricotta filling into the phyllo-lined dish.
Fold the overhanging phyllo over the filling, and give it a gentle brush of melted butter on top.
Bake for about 45 minutes until the crust is golden brown and crispy.