01 - Preheat oven to 350°F. Generously grease a 9x13-inch baking pan with melted butter, ensuring all corners are coated.
02 - Combine walnuts, almonds, pistachios (if using), sugar, cinnamon, and cloves in a large bowl. Mix thoroughly to distribute spices evenly throughout the nuts.
03 - Lay one phyllo sheet in the prepared pan. Brush lightly with melted butter. Repeat layering and buttering 6-8 sheets to form a sturdy base.
04 - Sprinkle one-third of the nut mixture evenly across the buttered phyllo surface, spreading to edges.
05 - Layer and butter 4-5 additional phyllo sheets. Add another one-third of the nut mixture, spreading evenly.
06 - Repeat with another 4-5 buttered phyllo sheets, then spread the remaining one-third of nut mixture across the surface.
07 - Finish with remaining phyllo sheets, buttering each sheet including the final top layer thoroughly.
08 - Using a sharp knife, cut baklava into diamond or square shapes before baking, slicing completely through all layers.
09 - Bake for 35-40 minutes until phyllo turns deep golden brown and becomes crisp throughout.
10 - While baklava bakes, combine sugar, water, and lemon juice in a saucepan. Bring to boil and cook 8-10 minutes until slightly thickened. Remove from heat and stir in honey and rose water if using.
11 - Immediately pour hot syrup evenly over hot baked baklava. Allow to cool completely at room temperature so syrup absorbs fully before serving.