You're going to need a shallow tray suitable for baklava, a bakery brush and a sharp knife.
Start with the syrup that you're going to be pouring over the hot baklava later. Mix together the water, sugar and lemon juice in a small pot. Once boiling, lower the stove and leave it to simmer while you prepare the baklava.
Mix 1 1/5 cups (300 g) of the ground to powder pistachios with the sugar and put the butter to melt. Then butter the bottom of the tray, start arranging sheets, while smearing each one entirely using the brush and so on until you've smeared 18 sheets with butter.
Pour on all of the filling and distribute it evenly all over, continue smearing with butter in the same fashion. Cut it into rhombuses or square pieces and pour on the remaining butter.
Turn the oven on to 392°F (200 °C) and bake 45 min. or until it swells up and the sheets turn golden and crunchy.
After you put the baklava in the oven, take the syrup off the stove and leave it to cool.
Once the baklava is ready, take the tray out of the oven. While it's still hot, pour the cold syrup over it evenly. Sprinkle with the remaining pistachios on top and leave it to cool completely before serving.