Use a large bowl and whisk the flour and salt. Cut the butter into the flour mixture using a pastry cutter, a fork, or two knives. Do this until you have a mixture of coarse crumbs
Add the eggs and knead for a minute or two and then slowly add about 1 ¼ cups ice water, a little at a time, until a ball a dough forms.
Using a lightly-floured surface, knead the dough until you have a large smooth ball. This should take about 5 minutes. Cover the bowl of dough with plastic wrap and let it rest for 30 minutes.
For the Filling
Using a large mixing bowl, add the meats and cheeses and eggs and mix thoroughly.
Putting the Pizza Rustica Together
Preheat your oven to 350° F and divide the dough into two balls. Use approximately ⅔ for the bottom crust and the remaining ⅓ for the top crust. Using a lightly floured surface, roll the bottom crust (larger portion) of the dough and then line the bottom and sides of a baking dish, leaving some overhang. Pour the filling mixture into the bottom crust and smooth it lightly. Use a little water to wet the edges slightly. This will make it easier to seal the top crust.
Next, you will roll out the remaining dough for the top crust. Place it over the filling and bottom crust, leaving some overhang which you can trim with a kitchen scissors. Tightly seal the edges of the top and bottom crusts and cut some vents in the top crust. Use a pastry brush to apply an egg wash and bake for 45 minutes. Take the pie out of the oven and apply another coat of egg wash and finish baking for another 45 minutes.
Allow this to cool completely before serving.
You can bake this Pizza Rustica in either a rectangle (10 x 14") baking dish, or a round 10" spring-form pan as shown.