Place a 12-inch cast iron skillet or 13"x9" casserole dish in the oven preheating to 400ºF.
In a medium bowl, blend together the egg, creamed corn, sour cream, and Jiffy. Remove the baking dish from the oven. Butter or spray with non stick cooking spray. Pour in the cornbread batter into the prepared dish and spread evenly.
Bake for 18-20 minutes or until golden brown.
While the base bakes, in a large skillet on medium-high heat, crumble and cook ground beef until no longer pink. Drain the grease, then stir in onion and seasonings. Cook 2 minutes. Stir in Manwich sauce and ½ cup water. Simmer on low for 5 minutes, then fold in ¼ cup of the shredded cheese.
Poke holes in the surface of the cooked cornbread base. Top with the beef mixture, spreading out evenly. Top with the remaining shredded cheese. Cover with aluminum foil and bake for 20 minutes.
Uncover and broil on high an additional 3-5 minutes. Remove from the oven and allow to cool for 10 minutes (otherwise it will fall apart when serving).
Uncover and broil on high for an additional 3-5 minutes. Remove from the oven and allow the pie to cool for 10 minutes. For a pop of color, garnish with sliced green onions or chopped fresh parsley.