• Thaw phyllo dough completely by placing it in the fridge overnight, then letting the package of phyllo sit, unopened, on the counter for 1 hour prior to making your baklava so it can come all the way to room temperature.  
• Butter the bottom and sides of a large rectangular 9x13-inch baking dish.  Trim phyllo to fit in the dish, if necessary.  I have seen 16 oz. pkgs. of phyllo that come with either 18 large sheets in one roll or 40 smaller sheets in 2 rolls.  Either works, so long as you have 16 oz. of phyllo.  I just cut the 18 large sheets in half down the middle to fit, giving 36 sheets.  The 40 smaller sheets might just need to be trimmed slightly around the edges.  Keep trimmed dough covered in a damp cloth so it doesn't dry out.
• Chop walnuts in a food processor by pulsing 10-12 times until coarsely ground or chop with a knife until very finely chopped.  Stir together the walnuts and cinnamon until combined.

Syrup

• Prepare the sauce before assembling the baklava so it has plenty of time to cool completely before pouring over the baked phyllo dough.
• Combine the sugar, water, honey, and lemon juice in a medium saucepan and bring to a boil over medium-high heat, stirring until the sugar dissolves.  
• Reduce heat to medium-low and continue to boil for 4 minutes more without stirring. Remove from heat and cool completely.
  

Baklava Assembly

• Heat oven to 325 degrees F.  
• Sprinkle approximately ⅕ of the chopped walnuts and cinnamon (roughly ¾ cup) in a thin, even layer over the first 10 sheets of phyllo dough.  
  
• Repeat 4 more times but with 5 sheets of phyllo dough instead of 10, brushing each with between before adding the next sheet and sprinkling with ¾ cup of the chopped walnut mixture between each layer of 5 sheets of buttered phyllo dough.
• Finish the baklava with a final, top layer of phyllo dough brushed with butter between the layers using the remaining 6-10 sheets of dough.  Brush the top sheet of phyllo dough with butter as well.  
• Carefully slice the baklava into 1 ½-inch wide strips lengthwise, then slice diagonally to create diamond-shaped baklava.  Or just slice squares if you prefer.  
  
• Bake in the 325 degree F oven for 1 hour and 15 minutes, until the baklava is golden brown.  Remove from oven and immediately drizzle all of the cooled syrup over the baklava.  
• Let the baklava cool completely at room temperature for 4-6 hours without being covered so the baked pastry can soak up all of the syrup.  The finished baklava can be store for 1 to 2 weeks at room temperature, covered with just a clean tea towel.