Preheat oven to 180 C. Butter the bottom and sides of a 23x33cm baking dish.
Toss nuts with cinnamon. Set aside.
Unroll filo pastry. Cut whole stack at once to fit the dimensions of the baking dish. Cover filo with a damp cloth to keep from drying out as you work. Place two sheets of filo in dish, buttering the top layer. Repeat until you have 8 sheets layered. Sprinkle 2 to 3 tablespoons of nut mixture on top. Top with two sheets of filo, butter, nuts, layering as you go. The top layer should be about 6 to 8 sheets deep.
Using a sharp knife, cut into diamond or square shapes all the way to the bottom of the dish. Bake for about 50 minutes until baklava is golden and crisp.
Make sauce while baklava is baking: Boil sugar and water until sugar is dissolved. Add honey and lemon peel. Simmer for 15 to 20 minutes, then remove from heat and allow to cool. Remove lemon peel and discard.
Remove baklava from oven and immediately pour cooled sauce over it. Let cool. Leave it uncovered as it gets soggy if wrapped.
For a little variation, you could use a combination of walnuts and almonds for this recipe.