Preheat the oven to 350°F (175°C). Grease a 9x13-inch baking dish with butter.

In a bowl, combine the chopped pistachios, walnuts, and cinnamon. Mix well and set aside.

Unroll the phyllo dough and cover it with a damp cloth to prevent it from drying out. Take one sheet of phyllo, brush it with melted butter, and layer another sheet on top. Repeat this process for 5 sheets.

Place a generous amount of the nut mixture along one edge of the phyllo dough. Roll the dough tightly over the filling to form a log. Place the log seam-side down in the prepared baking dish.

Repeat steps 3 and 4 until all the filling and phyllo dough are used, arranging the rolls side by side in the baking dish.

Brush the tops of the rolls with the remaining melted butter. Using a sharp knife, cut the rolls into 1-inch pieces.

Bake in the preheated oven for 30-35 minutes, or until golden brown and crisp.

While the baklava is baking, prepare the syrup. In a saucepan, combine honey, sugar, water, and vanilla extract. Bring to a boil, then reduce heat and simmer for about 10 minutes. Remove from heat and let cool.

Once the baklava is done baking, remove it from the oven and immediately pour the cooled syrup evenly over the hot rolls. Allow it to soak for at least 2 hours before serving.