Orange Masghati

Lightly butter a rimmed 1-2 inch deep dish (a regular pie plate works well). Set aside.

In a small bowl, combine 1 cup of the orange juice with the cornstarch. Stir until completely smooth, without any lumps, and set aside. In a medium saucepan, combine the rest of the orange juice (2 cups) and the sugar (if using) over medium- high heat, and bring to a simmer to dissolve the sugar.

Give the cornstarch slurry a final stir to combine, and add it to the pot. Reduce the heat to medium and start stirring immediately. Continue stirring until it starts to thicken and set, 5 minutes. Don't go anywhere during this process (the cornstarch sets quickly and can burn(. You'll know the mixture is ready when it coats the back of a wooden spoon. You don;t want it to get too thick as it will keep setting as it cools. Remove from the heat and immediately pour into the prepared dish and smooth over. Set aside to cool at room temperature, and place in the fridge, uncovered, for 6 to 8 hours to fully set and chill.

Meanwhile, to make the sauce, set a few raspberries aside as garnish and place the rest along with the sugar and hot water in a blender. Blitz the raspberries until smooth. Transfer to a small bowl, and store in the fridge until ready to use.

To serve, you can either run a butter knife around the rim of the dish and invert the masghati onto a serving platter or serve directly from the dish. Serve cold, topped with pistachios, the reserved raspberries, and a light drizzle of the raspberry sauce.

MAKE AHEAD: Masghati is best prepared up to 1 day in advance. It will keep, covered, in the fridge up to 3 days.