Place the sugar and water in a saucepan set over medium-high heat, stirring to help dissolve the sugar. Add the honey, cinnamon stick, and cardamom. Bring to a boil, then lower the heat and simmer for 10-15 minutes. Remove from the heat and stir in the lemon juice, then strain to remove the orange, cinnamon and cardamom. Set aside to cool.

Place an oven rack on the center shelf and preheat the oven to 350 degrees F.

In a food processor, pulse the walnuts and pistachios until finely chopped. Transfer to a large bowl and stir in the sugar, cinnamon, cardamom and salt until evenly combined.

Place the phyllo sheets on a clean surface and cover with a kitchen towel to keep them from breaking.

Brush the bottom of a 9x13 baking pan lightly with melted butter. Fold a sheet of phyllo in half and place it in the baking pan and brush lightly with butter. Repeat the process with 4 more sheets, for 8 layers total. Top with half the nut mixture, spreading it evenly across the phyllo.

Top with 5 more phyllo sheets, folded in half, again brushing each layer with butter. Spread the remaining nut mixture evenly over the phyllo. Repeat with the remaining phyllo sheets, brushing butter in between each layer, until they’ve all been used.

Using a sharp knife, cut the baklava into diamond shapes or squares, about 1 to 1 ½ inches wide. Drizzle any remaining butter over the top.

Bake for 40 - 50 minutes until the top golden brown. Remove from the oven and immediately pour the syrup evenly all over the baklava.

Allow the baklava to sit at room temperature for several hours (or 1 hour minimum) before serving. Garnish with finely chopped pistachios.