Whisk the milk, sugar, and cornstarch together in a 2-quart / 1.9 L saucepan until smooth.

Set the pan over medium heat and cook, whisking constantly, for 6 to 8 minutes until the mixture thickens into a pudding that coats the back of a spoon.

Remove from heat and stir in the heavy cream and orange blossom water. Pour into a shallow dish, press plastic wrap directly onto the surface, and chill for at least 1 hour until firm.

Combine the sugar, water, and lemon juice in a clean 2-quart / 1.9 L saucepan. Bring to a boil over medium-high heat, then lower the heat and simmer for 5 minutes until slightly thickened.

Remove from heat and stir in the rose water and orange blossom water. Cool completely, then refrigerate until cold, the syrup needs to be cold when the fried rolls hit it.

Lay one phyllo sheet on a work surface and cut into three even rectangles, about 10 x 12 cm / 4 x 5 inch each. Keep the rest of the phyllo covered with a damp towel so it doesn't dry out and crack.

Place 1 heaping teaspoon of chilled ashta filling near one short edge of a phyllo rectangle. Fold the long sides in over the filling, then roll up tightly into a cigar shape.

Brush the loose edge with beaten egg white using a pastry brush to seal. Repeat with the remaining phyllo and filling, you should get about 20 to 24 rolls.

Heat 5 cm / 2 inches of oil in a 3-quart / 2.8 L heavy pot to 350°F / 175°C. Fry the rolls in batches of 5 to 6, without crowding the pot, for 2 to 3 minutes, turning once, until deep golden brown.

Lift the rolls out with a slotted spoon and drop them straight into the cold syrup for 20 to 30 seconds per side.

Transfer to a wire rack or platter. Scatter crushed pistachios over the top and serve warm or at room temperature.