Preheat oven to 350 degrees F.

Butter the bottom and sides of a 9x13 inch pan.

Unroll phyllo dough and cover with a damp cloth.

Fold a phyllo sheet to fit the pan.

Place the folded sheet in the pan and brush with butter.

Repeat layering with 3 more phyllo sheets, buttering each layer.

Sprinkle 2-3 tbsp of ground walnuts on top.

Repeat the phyllo layering and walnut sprinkling 2 more times.

Top the last layer of nuts with a folded phyllo sheet and butter it.

Repeat layering with remaining phyllo sheets, buttering each.

Cut the baklava into diamond or square shapes.

Bake for 40-45 minutes, or until golden brown and crisp.

While baklava bakes, prepare the syrup.

Boil sugar and water until sugar dissolves.

Optionally dissolve saffron in hot water and add to the syrup.

Add cardamom to the syrup and simmer for 15 minutes, until slightly thickened.

Add rose water and simmer for 1 minute.

Remove from heat and add lemon juice.

Let the syrup cool.

Remove baklava from oven and immediately pour cold syrup over it.

Decorate with crushed pistachios or coconut powder.

Let cool completely before serving.

Do not cover until fully cooled.

Syrup can be made in advance and stored in the fridge.