Pomegranate Masghati Dessert

Set aside a 9- to 10-inch, 1- to 2-inch-deep serving dish (a regular pie plate works). Whisk 1 cup pomegranate juice with cornstarch in a small bowl until completely smooth, without any lumps; set aside.

Combine sugar and the remaining 2 cups pomegranate juice in a medium saucepan. Bring to a simmer (little bubbles start to appear on the sides) over medium-high heat; cook, stirring, until the sugar dissolves, about 5 minutes.

Whisk the cornstarch mixture and add it to the saucepan. Reduce the heat to medium-low and start stirring immediately. Continue to stir until it starts to set, 2 to 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 lightly coats the back of a spoon. You don't want it to get too thick, as it will keep setting as it cools. At the very last moment, add rose water (if using) and pomegranate seeds; stir to combine and remove from the heat.

Immediately pour the masghati into the serving dish and smooth the top. Set aside to cool to room temperature, then refrigerate, uncovered, to fully set and chill, 6 to 8 hours. Once chilled, garnish with pomegranate seeds, pistachios and rose petals, if desired, and serve cold.