Bring a large pot of lightly salted water to a boil. Add ziti pasta, and cook until al dente, about 8 minutes; drain.
In a large skillet, brown onion and ground beef over medium heat. Add spaghetti sauce, and simmer 15 minutes.
In medium bowl, stir together ricotta, sour cream, egg & Italian seasoning.
Spray one jumbo or two large aluminum foil pans with cooking spray.
Layer ingredients as follows:
Half of the sauce
Half of the ziti
Half of the Provolone cheese,
Half of the mozzarella
Layer remaining sauce, ziti, provolone & mozzarella.
Spread all of ricotta/sour cream mixture on top.
Sprinkle parmesan on top.
Bake at 350 degrees until bubbly.
IF FREEZING:
Assemble (but do not cook) ziti.
Wrap well, label, and freeze.
TO COOK FROM FROZEN:
Place in fridge to thaw a few days before serving.
Bake at 350 until bubbly.
Allow to rest at least a half hour before serving.
