Bellawriyeh is one of my quickest and easiest sweets; mouthwatering sticky phyllo pastry squares stuffed with flavorful pistachio-walnut filling and finished with rose water and orange blossom syrup. I love the chewy, crunchy texture and decadent combination of orange blossom–rose water syrup with the mixed nuts. Although Bellawriyeh is traditionally prepared only with pistachios, Mama and I fell in love with the combination of nuts—if you prefer just pistachios, omit the walnuts altogether. 
MAKES THIRTY 2-INCH SQUARES
1 pound Athens Shredded Fillo Dough (kataifi, see Resources), thawed in the box at room temperature for 1 hour
2 cups raw, shelled, unsalted whole pistachios
2 cups raw, unsalted whole walnuts
1 cup sugar
½ cup warm Samneh (Clarified Butter, here)
1 tablespoon rose water (see here)
1 tablespoon orange blossom water
3 cups Ater rose water and orange blossom syrup (see here)
Preheat the oven to 375°F.
Bring 6 cups of water to a rolling boil in a large pot, and place a double boiler, steamer basket, or heatproof bowl over the pot of boiling water. Reduce the heat to low and maintain a steady simmer.
Remove the phyllo (kataifi) from the box and sealed bag, and separate the dough into two equal parts over a large baking sheet, making sure not to tear through the shredded strands. Place each half of the kataifi, one at a time, in the bowl or steamer basket and steam for 2 to 4 minutes, tossing the dough with tongs occasionally just until the kataifi is soft, pliable, and moist. Remove the dough with tongs and set aside on a separate baking sheet.
Pour 2 tablespoons of the warm clarified butter over each half (4 tablespoons total) and gently toss with tongs to coat the kataifi completely. Set aside.
Grind the pistachios, walnuts, and sugar in a food processor into a coarse, chunky consistency and transfer to a large mixing bowl. Pour 2 tablespoons of the clarified butter over the mixture in addition to 1 tablespoon of rose water and 1 tablespoon of orange blossom water. Stir to incorporate all the ingredients—the mixture should be moist—and set aside.
Butter the bottom and sides of a 9 x 13-inch baking pan with 2 tablespoons of clarified butter. Completely cover the bottom and corners of the buttered pan with one half of the kataifi, firmly pressing into it with the palms of your hands so that it sticks together and is flattened into one solid piece. Then, pour the nut mixture into the center of the kataifi and spread it in an even single layer using the back of a silicone spatula or spoon. Now, cover the nut mixture with the remaining half of kataifi, firmly pressing it down with your palms to completely cover the nuts. To finish, drizzle the remaining 2 tablespoons clarified butter over the top.
Place a piece of parchment paper over the pastry dough, and place a baking pan or heavy plates on top of the parchment to weigh it down. Refrigerate for at least 2 hours or overnight until it sets and becomes very cold.
Once the kataifi mixture has adequately chilled, preheat the oven to 350°F.
Remove the pan from the refrigerator, remove the weights, and peel off the parchment paper. Place the pan on the center rack of the preheated oven and bake for 30 to 35 minutes until light golden white in color, and not at all browned.
Remove from the oven and glaze with the rose water and orange blossom syrup until all of the syrup is soaked in and the top is glistening.
Allow the Bellawriyeh to completely cool before serving, 2 to 3 hours. Then, slice into small, even squares; you should have 30.
Store at room temperature if serving within a week, or refrigerate for up to 14 days.
Note You will need a pastry brush, two 9 x 13-inch baking pans (or 1 baking pan and two heavy plates to use as weights).