In a food processor add the walnuts, almonds and hazelnuts. Pulse a few times to chop. Then add sugar and honey. Mix well to combine.
Unroll the thawed phyllo pastry and place the sheets in between two clean kitchen towels. This will help keep the phyllo from breaking while you work.
Prepare a 9”x 13” baking pan. Brush the baking pan with some of the melted butter. To assemble the baklava, take one sheet of phyllo and place it in the pan. Brush the top of the phyllo sheet with the melted butter.
Repeat this process a few more times until you have used up about 1/2 of the phyllo pastry, each layer being brushed with the melted butter.
Add the nut mixture evenly over the top layer of phyllo.Continue assembling the baklava, one sheet of phyllo pastry at a time brush each layer with a bit of the melted butter. Using a sharp knife, cut the pastry into 24 pieces.
Place the baking dish on the middle rack of your heated oven. Bake anywhere from 35 to 45 minutes or until the top of the baklava turns golden and a skewer inserted in the centre comes out clean.
As soon as you remove the baklava from the oven, pour the cooled syrup all over the hot baklava.
Allow the baklava to sit for a few hours before serving or for at least 2 hours through the earlier marked pieces.