01 - Preheat oven to 350°F. Generously grease a 9x13-inch baking pan with melted butter.
02 - Combine walnuts, almonds, pistachios (if using), sugar, cinnamon, and cloves in a bowl. Mix thoroughly to distribute spices evenly.
03 - Place one phyllo sheet in the prepared pan. Brush lightly with melted butter. Repeat, layering and buttering 6-8 sheets total for the bottom layer.
04 - Sprinkle one-third of the nut mixture evenly across the buttered phyllo sheets.
05 - Layer and butter 4-5 additional phyllo sheets. Spread another one-third of the nut mixture over the dough. Repeat with another 4-5 buttered sheets and the remaining one-third of nuts.
06 - Layer remaining phyllo sheets, brushing each with melted butter including the very top sheet.
07 - Using a sharp knife, cut baklava completely through into diamond or square shapes before baking.
08 - Bake for 35-40 minutes until layers are golden brown and crisp.
09 - While baklava bakes, combine sugar, water, and lemon juice in a medium saucepan. Bring to a boil and cook for 8-10 minutes. Remove from heat and stir in honey plus rose or orange blossom water if using.
10 - Immediately pour hot syrup evenly over the hot baked baklava. Allow to cool completely at room temperature so syrup absorbs fully before serving.