Preheat oven to 350 degrees F. Lightly grease a 9x13 pan.
Combine all syrup ingredients in a small saucepan and bring to a boil over high heat. Reduce heat to medium low and simmer until slightly thickened, about 5 minutes. Set aside.
Use a food processor to chop the nuts into small, even sized pieces. Stir 1/3 cup sugar and cinnamon into the chopped nuts until well combined.
Melt the cannabis butter and butter together.
As phyllo dough dries fast, keep it covered with a damp kitchen towel while you are working. If necessary, cut the dough so the sheets will fit in the baking pan. Place a sheet of phyllo dough into the pan. Use a pastry brush to brush the phyllo sheet with the melted butter mixture. Repeat 7 more times until the stack is 8 sheets thick. Spread a thin layer of the nut mixture over the dough. Cover with two more sheets of phyllo, brushing each one with butter. Continue to repeat adding a layer of the nut mixture then a phyllo sheet, butter and another phyllo sheet, until the nut mixture is used up. Finish up with 8 more sheets of phyllo dough, brushing each with butter as you add them.
Take a sharp knife and cut the baklava into 24 pieces in the pan. Bake for about 30 minutes or until lightly golden brown.
Spoon the cooled syrup over the hot baklava and sprinkle with chopped pistachios, if using. Let cool for at least 2 hours before removing to a serving dish.