Adjust middle rack to center position and preheat the oven to 350.
Gently melt 6 - 7 T butter on the stove-top or in the microwave.
Cut a circle of parchment paper the size of the removable bottom and line the bottom of the pan. Brush a small amount of melted butter on the sides and bottom of an 11-inch tart pan. Get the butter into all the fluted edges. Put in the parchment paper disc and brush with melted. This will make it easier to slide the tart off the bottom of the pan.
Blitz the shelled pistachios, Graham crackers, sugar, ground cardamom, and salt in a food processor until the ingredients become fine crumbs.
With the food processor running, slowly pour in 6 - 7 T melted butter. The mixture should adhere to itself when pressed. If it does not, add a little more melted butter.
Dump the crust mixture into the bottom of the prepared 11-inch tart pan and using the flat bottom of a cup, press it evenly into the pan and up the sides. Press hard.
Bake the crust 8 - 12 minutes.
Put a flat baking sheet in the oven and let it preheat while you prepare the lemon filling. The lemon tart will bake on the already hot baking sheet. This method helps to keep the bottom crust crisp.