Open the phyllo pastry dough package and cover with a damp towel to prevent drying out. If needed, trim the dough to fit your glass baking dish.
Grease a 13 x 9-inch or larger glass baking dish with 1 tablespoon of the melted butter and set aside.
In a medium saucepan, combine the sugar, water, honey, and lemon juice. Bring to a boil over medium-high heat, stirring often until the sugar is dissolved. Reduce the heat to low and simmer without stirring for 4 minutes; set aside to cool.
Preheat oven to 325F degrees.
Combine the finely chopped walnuts and cinnamon in a medium bowl.
Lay 1 sheet of the phyllo dough into the bottom of the buttered dish. Brush with melted butter, then repeat with 9 more sheets of phyllo. Spread ¾ cup of the walnut mixture evenly over the phyllo layer.
Lay another 5 sheets of phyllo dough over top of the walnut mixture, brushing each with butter. Sprinkle on another ¾ cup of the walnut mixture.
Repeat until walnut mixture is used up, then top with 10 last sheets of phyllo dough, brushing butter on each as you add them.
Brush the top layer with butter, then slice the pastry into 1 1/2 inch strips and then slice diagonally in both directions to create diamonds.
Bake uncovered for 1 hour 25 minutes until pastry is golden brown.
Immediately after removing from the oven, pour the cooled syrup over the pastry.
Let cool completely before serving. For best results, let the baklava sit covered overnight to soak up the syrup.