Trim filo pastry dough to fit your 13 x 9-inch baking dish and cover it with a damp towel to keep it moist.

Preheat your oven to 325 degrees F and grease your baking dish with 1 tbsp. of melted butter.

In a medium saucepan, combine the sugar, lemon juice, water, and honey over medium-high heat. Bring it to a boil, stirring to dissolve the sugar, then reduce heat to medium-low and let it simmer for about 4 minutes without stirring. Allow it to cool.

Pulse walnuts in a food processor until finely chopped. Mix the nuts with cinnamon in a medium bowl and set aside.

Layer 10 sheets of filo dough into the greased baking dish, brushing melted butter between each sheet. Spread 3/4 cup of the walnut mixture over this layer.

Add another 5 sheets of buttered filo, followed by another 3/4 cup of walnuts. Repeat this until you use up the walnut mixture, finishing with 10 more sheets of buttered filo dough.

Brush the top layer with butter, then slice the baklava into 1 1/2-inch strips and cut diagonally to create diamond shapes.

Bake uncovered for 85 minutes until the pastry is golden.

Drizzle the cooled honey syrup over the baked baklava while it’s still hot, letting it soak in.

Allow it to cool completely before serving.