For The Crust
Mix flour and sugar together (and salt if needed) until fully incorporated.
Add butter and squeeze together until butter bullets are formed.
Begin by adding 2 tbsp ice water and mixing, adding more if necessary. Mix until a shaggy mass is formed.
Turn dough out onto a floured surface and roll out until slightly larger than the diameter of the pie pan.
Spray pie pan and place crust inside.
Even crust out, and then shape and flute (see above).
For The Filling
Preheat oven to 375*
Cook fillings, using salt as needed. Set aside.
Whisk together eggs, milk, and salt.
Place fillings into finished crust, and then pour egg mixture on top.
Lightly stir to ensure incorporation.
Add cheese to top, if using.
Bake for 40-60 minutes, until liquid is springy and no longer jiggles when nudged, and crust and surface are nicely browned.