In a medium bowl, combine nuts and cinnamon. Set aside.
Lightly brush the bottom and sides of a 9″ x 13″ baking pan with melted butter.
Place half of the phyllo sheets (about 20 sheets) on the bottom of the pan, lightly brushing every (or every other) sheet with melted butter. NOTE: The number of sheets may vary depending on the brand of phyllo dough used.
Spread the nut mixture evenly on the phyllo dough.
Layer the rest of the phyllo sheets (about 20 more sheets) on top, lightly brushing each sheet. Generously brush the top layer with melted butter.
Place tray of unbaked paklava in refrigerator for about 45 minutes to one hour before attempting to cut.
To make diamond-shaped cuts, use a very sharp knife and cut diagonally through the layers of phyllo dough, then make vertical cuts through the dough.
Bake in a preheated 350°F oven for 45 minutes to 1 hour or until golden brown.
As soon as the paklava comes out of the oven, spoon some of the cooled syrup over the top of each piece. Cool completely before serving.