How to Make It
Add pistachios to the bowl of a food processor and process until coarsely chopped. Remove ½ cup of the chopped nuts and set aside, then grind the remaining nuts until they form a thick, malleable paste, about 3 minutes. Mix the paste with the reserved chopped nuts, 2 teaspoons of sugar, and cardamom.
Place one sheet of thawed phyllo dough on a clean counter and brush lightly with melted butter. Cover with another sheet and repeat the process until you have 5 sheets of dough layered together. Spoon 3 tablespoons of the nut mixture in a line along the short side off the dough, then roll the dough tightly around the nuts, continuing until you've used half of the sheet of dough. Slice the along the roll to separate it from the remaining dough, then cut the roll crosswise into 4 pieces. Continue the process, making another roll with the remaining dough, then repeat the whole process four more times to use up the rest of the phyllo, butter, and filling.
Heat the oven to 350°. Brush a 9”x13” baking pan with butter, then fill it with the phyllo rolls packed in one even layer. Brush the rolls with butter. Bake until golden, about 35 minutes.
While the rolls are baking, combine the remaining 2 cups of sugar, orange juice, and 1½ cups water in a medium saucepan. Cook over medium heat, stirring occasionally, until the mixture begins to boil. Lower heat and let simmer for 15 minutes.
Remove the rolls from the oven and drizzle with the syrup. Let the baklava sit until it has absorbed the liquid, about 1 hour, then sprinkle with ground pistachios before serving.