01 - Preheat your oven to 350°F. Generously grease a 9x13-inch baking pan with melted butter, ensuring all corners and sides are coated.
02 - Combine walnuts, almonds, pistachios (if using), sugar, cinnamon, and cloves in a large mixing bowl. Mix thoroughly to ensure even distribution of spices throughout the nuts.
03 - Lay the first phyllo sheet in the prepared pan. Brush lightly and evenly with melted butter. Continue layering and buttering 6-8 sheets, ensuring each sheet is completely coated with butter.
04 - Spread one-third of the nut mixture evenly across the buttered phyllo base, covering the entire surface area.
05 - Layer and butter 4-5 additional sheets of phyllo dough. Add the second third of the nut mixture, distributing evenly.
06 - Repeat with another 4-5 buttered phyllo sheets, followed by the final third of the nut mixture. Ensure the nuts are spread uniformly for consistent layers.
07 - Finish with the remaining phyllo sheets, brushing each generously with melted butter, including the very top sheet which should be thoroughly coated for golden browning.
08 - Using a sharp knife, carefully cut the assembled baklava into diamond or square shapes. Cut through all layers to the bottom of the pan. This prevents crumbling after baking.
09 - Bake for 35-40 minutes until the phyllo turns deep golden brown and becomes crisp throughout. Rotate the pan halfway through for even browning.
10 - While baklava bakes, combine sugar, water, and lemon juice in a medium saucepan. Bring to a boil and cook for 8-10 minutes until slightly thickened. Remove from heat and stir in honey and rose water or orange blossom water if using.
11 - Immediately pour the hot syrup evenly over the hot baked baklava. Allow to cool completely at room temperature, letting the syrup absorb fully into the layers before serving.