In a food processor, process the nuts until they are finely ground. Toss them into a bowl with the sugar and salt.
Preheat the oven to 350 F.
Trim the phyllo so it’s about 11-12 inches wide then cover it with a damp towel. Melt the ghee if it’s in a ‘creamy’ or solid state.
Brush a deep 9" springform pan with a thin layer of ghee, then place a phyllo sheet over the bottom, it’s fine if it has some overhang - we’ll trim it later. Brush the sheet of phyllo with ghee and layer another sheet over it, turning it slightly, and brush. Keep doing this until you have 15 layers of phyllo, layering them so you’re getting coverage on all sides of the pan.
After the 15th sheet, spread half of the nut mixture into an even layer. Brush one sheet of phyllo with ghee and layer it, ghee side down, on top of the nuts then brush the top with ghee. Layer and brush again, with another 8 sheets. Spread the other half of the nut mixture on top of the 8th layer and then brush and layer again, for another 7 phyllo sheets.
Trim any excess phyllo that’s hanging over the edges (in the video you’ll see I trimmed it a bit but I also had to trim more after I baked it) and then use a sharp knife to slice through the baklava, cutting it like a pie into 16 thin wedges. Brush more ghee on top after slicing.
→Note: these slices won’t necessarily be the slices for the cheesecake once it’s done, but the cuttings allow for the syrup to seep in to make this more of a true baklava crust.
Set the springform pan on a cookie sheet and bake it until golden all over, for about 30 minutes. While it’s baking, make the syrup: cook the sugar and water together until the sugar dissolves then remove from heat and squeeze in the lemon juice. Let it cool.
When the crust is done baking, remove it from the oven and drizzle the syrup all over - ensuring to get syrup into all the cracks. Let cool completely before making the filling.