Preheat oven to 160 °C/ 325 °F
Place nuts in a food processor. Pulse to make fine crumbs but don't let it turn into powder.
Cut and trim phyllo sheets according to the size of the baking dish.
Brush base of pan/dish with butter. Lay over one sheet of phyllo. Brush with butter. Repeat for 10 sheets, brushing every single sheet with butter. Scatter over 3/4 cup walnuts.
Cover with 4 sheets of phyllo, brushing every sheet with butter. Top with 3/4 cup walnuts. Repeat 4 more times.
Lastly cover with 10 sheets, brushing them with butter.
Using a sharp knife cut it into squares or diamond shape.
Bake for around 1 hr until light golden.
Remove from oven and immediately pour the cool syrup over.
Leave to soak for at least 4-5 hours, preferably overnight.