In a medium saucepan over medium heat, place the milk, semolina and sugar. Stir frequently until the mixture is fully dissolved and creamy, about 20 minutes. Be careful not to let the milk boil. Stir in the orange blossom water.
Transfer the semolina pudding to an 8x11 baking dish and use the back of a spoon or spatula to spread the mixture to an even layer. Press a plastic wrap directly on the surface of the pudding to prevent a skin from forming and allow it to come to room temperature, about 15 minutes.
Remove the plastic wrap from the semolina pudding, spoon the ashta on top of the pudding and sprinkle with pistachios all over. Cover lightly with plastic wrap, and allow the pudding to cool completely in the fridge, at least 2 hours.
When ready to serve, cut the pudding into 12 squares and drizzle each serving with simple syrup.
Storage:Cover the dish with plastic wrap or a lid and place it in the refrigerator, storing up to 3-4 days.Toppings: Instead of the ashta, you can use whipped cream or ricotta. You can also top semolina pudding with fresh fruits or chocolate shavings. Be creative and experiment with different toppings to suit your taste preference.Swap the aromatics. Rose water is a substitute for orange blossom water and rose petals can be added for decoration. If you can’t find either of these floral essences, you could also use a small amount of vanilla or almond extract.Switch the nuts: Instead of crushed pistachios, you can use chopped almonds, walnuts, or hazelnuts. You can also add raisins or other dried fruits for extra texture and flavor.Add spices: You can add a pinch of ground cinnamon, cardamom, or nutmeg to the semolina pudding for a warm and aromatic flavor.