With the rack in the middle position, preheat the oven to 180°C (350°F). Butter a 23 x 33-cm (9 x 13-inch) Pyrex or aluminum baking dish.
In a bowl, combine the nuts, cranberries and spices. Set aside.
Slice the sheets of phyllo in half to obtain rectangles the same size as the baking dish.
Lay one third of the phyllo (about 13 sheets) in the baking dish, brushing each sheet with butter. Spread half the nut mixture over the dough. Repeat with another third of the phyllo and the remaining nut mixture. Cover with the remaining dough (also buttered).
Using a very sharp knife, cut into 15 squares. Cut each square diagonally into 2 triangles.
Bake for about 45 minutes.
In a saucepan, bring all the ingredients to a boil, stirring until the sugar dissolves. Pour over the hot baklava. Let cool to room temperature.