Thaw frozen phyllo sheets according to package instructions. I kept them in the fridge overnight. Then put the package on the counter about 1 hour before making the baklava. Make sure to leave them in the package, they will dry out if left out.
Toast all the nuts until fragrant, about 4~5 minutes. Let cool and grind in a food processor until fine. Set aside.
Melt butter and keep ready.
Microwave Nutella until spreadable and keep ready.
Preheat the oven to 350°F. Brush melted butter on a 10"x15" baking pan. If using 9"x13" pan, you might have to cut the phyllo pastry a little bit to fit the pan.
Place one phyllo sheet in the baking pan and brush with melted butter. Place another sheet and brush with butter. Repeat until you have 6 layers of phyllo. Spread 1/3 of the Nutella on top and sprinkle with 1/3 of the nut mixture.
Repeat the layering process: 6 sheets of phyllo (each brushed with butter) + Nutella + Nuts.
So in the end this is how the baklava should be: 1. 6 sheets of phyllo (each brushed with butter) + Nutella + Nuts 2. 6 sheets of phyllo (each brushed with butter) + Nutella + Nuts 3. 6 sheets of phyllo (each brushed with butter) + Nutella + Nuts 4. 6 sheets of phyllo (each brushed with butter)
Brush the top most layer of phyllo with butter. Using a sharp knife cut the phyllo into squares or diamonds. Bake for 35 minutes or until the phyllo pastry is golden brown on top and crispy around the edges.
While Baklava is baking make the syrup. Combine water, honey and cinnamon stick in a small saucepan, bring to a boil. Lower the heat and simmer for 5~7 minutes. Turn off the stove and keep ready.
Once the baklava comes out of the oven, pour the warm syrup evenly over the baklava. Set aside for 3~4 hours for the flavors to mingle. Enjoy!!