Pastry Crust: Pulse flour, oregano and pepper in a food processor; scatter butter over flour mixture and pulse until butter is cut into the flour and resembles pea-sized crumbs. Add eggs; pulse to combine. Add water, 1 tablespoon at a time, pulsing after each addition until mixture holds together when pinched with fingers. Knead dough on floured work surface 5 minutes; shape into 2 equal-sized disks and wrap with plastic wrap. Refrigerate dough at least 1 hour or up to 1 day.

Pie Filling: Heat oil in a large sauté pan over medium heat; add onion and cook 3 minutes, stirring frequently. Add sausage; cook until browned, about 8 minutes, stirring occasionally. Transfer sausage and onion to a plate; cool completely. Whisk eggs in a bowl and reserve 1 tablespoon egg; stir in ricotta cheese, fontina cheese, kale, peppers, sausage and onion.

Spray 9-inch springform pan with pan spray. Lightly flour work surface and rolling pin. Roll 1 disk of dough into a 16-inch circle; lightly press onto bottom and sides of pan, leaving 1-inch overhang. Layer half the sandwich prosciutto and sopressata in bottom of dough-lined pan; add egg-mixture and top with remaining sandwich prosciutto and sopressata.

Roll remaining disk of dough into a 12-inch circle; carefully place over filling. With scissors, trim edges of dough, leaving a 3/4-inch overhang. Fold excess top crust dough under bottom crust and flute to seal.

Brush top of pie with reserved egg; with paring knife, cut 4 (1-inch) vents in top crust. Bake pie at 375°F until crust is golden brown, about 1 hour. Reduce oven temperature to 300°F. Tent pie with foil; bake until internal temperature reaches 165°F, about 30 minutes. Cool completely on wire rack; remove springform pan and cut into 10 wedges. Wrap with plastic wrap; refrigerate up to 3 days.

For serving, serve pie at room temperature or reheat at 350°F until heated through.