Directions

1. SPECIAL EQUIPMENT: KitchenAid® Artisan Stand Mixer with pastry beater attachment; mini tart pan; pastry brush
2. In a small bowl, whisk together the cornstarch, powdered sugar, water, egg, lemon juice, and vanilla. Set aside.
3. Place the mascarpone cheese, parmesan cheese, cream cheese, salt, butter, and milk in the saucepan and turn to medium heat. Whisk the mixture as it all melts together. Once all the cheese is melted and the mixture is smooth (about 3 minutes), remove 5 tablespoons of the hot mixture, 1 tablespoon at a time, and whisk each tablespoon into the milk mixture to temper it. Then, add the tempered milk mixture into the pan with the remaining cheese mixture, whisking constantly as you pour. Continue to cook and whisk until the mixture thickens into custard consistency and the whisk leaves indentations. Remove the mixture from the heat and pour the mixture into a shallow dish. Butter the center of a piece of plastic wrap slightly larger than the bowl, and place the buttered side down on top of the cheese custard. (This will prevent a crust from forming on top of the filling.) Chill the custard in the refrigerator for at least an hour, or until cool to the touch.