Melt the butter ahead of time. Chop the walnuts using a food chopper.
Take 1 phyllo pastry sheet and smear it generously with butter everywhere. Sprinkle with walnuts on top. Roll it up carefully using a thin rolling pin.
Once it's all rolled up, begin to press on it starting from both ends and going toward the middle, then carefully remove the baklava from the rolling pin. Arrange in a pre-buttered tray.
Repeat this process for the rest of the sheets, placing them next to each other in the tray. Before you put them to bake, smear them with melted butter on top. Bake in a preheated 356°F (180 °C) oven about 30 min.
Once you take the baklava out, cut it with a knife and leave to cool.
Once the baklava has cooled, pour hot syrup over it, made as follows: mix all the ingredients for the syrup and leave them to boil about 5 min.