Mix and knead together all of the dough ingredients–by hand, in a mixer, or in a bread machine–till you’ve made a soft, smooth dough. Place the dough in a lightly greased bowl, cover, and allow it to rise for 1 to 2 hours, till it’s doubled in bulk.
While the dough is rising, make the filling. Stir together the eggs, ricotta, mozzarella, Parmesan, salt, and pepper. Stir in the ham, salami, and pepperoni. Divide the filling in half (each about 4 1/2 cups, about 2 1/2 pounds), and refrigerate. Preheat the oven to 325°F. Get out two 9” pie pans.
Gently deflate the dough, and divide it into four pieces. Two of the pieces will be bottom crusts, and should be just slightly larger than the other two pieces. Place one of the larger pieces of dough on a lightly greased silicone rolling mat, or lightly greased work surface. Roll it into a circle that’s about 16” in diameter; go away for 5 minutes, then come back; the circle will probably have shrunk. Roll it out again, and drape it into the pie plate, anchoring the edges to the pan by folding them underneath the rim; you don’t want it shrinking down the sides of the pan while you’re rolling the other crust. Roll one of the smaller pieces of dough the same way you did the larger, giving it time to shrink and then rolling again, if necessary
Line the bottom crust with half the prosciutto slices. Spoon half the filing on top. Drape the top crust over the filling, and bring the edge of the bottom crust up over the edge of the top crust, sealing the two together and smoothing them as best you can. Cut a 1” circle in the center of the top crust, to allow steam to escape. Make another pie with the remaining dough and filling.
Place both pies on a large, parchment-lined baking sheet; if you don’t have a big enough sheet, use two. The baking sheet makes it easier to transport pies in and out of the oven, and parchment will catch any spills.
Bake the pies for 80 minutes, until they’re a light golden brown. Five minutes before the end of the baking time, remove them from the oven, brush or spray with olive oil, and return to the oven; this will give the crust a nice glow. Remove the pies from the oven, and let them rest for at least 1 hour (preferably 2 hours) before cutting. Serve warm, or at room temperature