Cook your sausage, and spread it out evenly in a 10x10 baking dish.
Cut your provolone, salami, and mozzarella into small cubes, then layer them one at a time in the baking dish.
Spread the ricotta out evenly on top of the other ingredients before adding the eggs. Poke the frittata with a knife or fork all over so the egg begins to soak in. If the egg is not covering the other ingredients well, add more egg.
Bake for one hour, until nicely browned on top and the egg is cooked through.
Make sure to use whole milk ricotta, so the ricotta layer is nice and firm.