For the crust:
Preheat the oven to 325°F (163°C). In a medium bowl, combine the graham cracker crumbs, sugar, and melted butter until well mixed. Press into the bottom of a 9-inch springform pan. Bake for 8-10 minutes until lightly golden. Set aside to cool.

1. For the cheesecake filling:
   In a large bowl, beat the softened cream cheese with an electric mixer until smooth. Add sugar and vanilla, mixing well. Add eggs one at a time, mixing after each addition. Add sour cream and heavy cream and mix until smooth. Pour the filling into the cooled crust and smooth the top.
2. Bake the cheesecake at 325°F (163°C) for 50-60 minutes or until the center is set but slightly jiggly. Turn off the oven and let the cheesecake cool for 1 hour. Refrigerate for at least 4 hours or overnight to fully set.
3. For the baklava topping:
   Preheat the oven to 350°F (175°C). Lay a sheet of phyllo dough on a clean surface and brush lightly with melted butter. Continue layering and buttering phyllo dough sheets, sprinkling a mixture of chopped walnuts, pistachios, and cinnamon every few layers. Once all dough and nut mixture is used, bake for 20-25 minutes until golden and crispy.
4. While the baklava is baking, make the honey syrup by combining honey, water, and lemon juice in a saucepan. Simmer for 5-7 minutes until slightly thickened.
5. Once the baklava is baked, drizzle the honey syrup over the top and allow it to cool completely.
6. Assemble the Baklava Cheesecake:
   Once the cheesecake has chilled and the baklava topping has cooled, carefully transfer the baklava on top of the cheesecake. Gently press down to adhere the layers. Slice and serve.