Prepare Syrup: Heat sugar and water until dissolved. Add lemon juice and simmer for 10 minutes. Cool completely.
Prepare Nuts: Chop pistachios finely. Set aside.
Layer the Phyllo Dough: Brush a baking dish with butter. Place 10 layers of phyllo, brushing each with butter. Spread half the nuts evenly. Add another 10 buttered phyllo layers and spread the remaining nuts. Finish with 10–12 buttered layers.
Cut Before Baking: Slice into diamonds or squares using a sharp knife.
Bake: Bake at 170°C for 45–50 minutes until golden and crisp.
Add Syrup: Pour cooled syrup evenly over hot baklava. Let it rest at least 6 hours (preferably overnight).
Serve: Garnish with crushed pistachios. Serve with Turkish tea or coffee.