Cornbread & Sausage Wheel without shells

12 tablespoons butter (1 1/2 sticks) 2 cups finely-chopped yellow onions 3 tart apples , cored and chunked, but not peeled (Jonathan, Winesap or Granny Smith)[...]

2 cups yellow cornmeal 2 cups all-purpose flour 1/2 cup sugar 2 tablespoons baking powder 2 teaspoons salt 2 cups milk (do not use nonfat) 2/3 cup vegetable[...]