Chicken and Corn Bread Casserole

I made this last night and I thought it was pretty good. The recipe comes from my Simply the Best Chicken cookbook freebie from Gold Kist Farms. While it was good as-is, if I ever make it again, I'll make a few changes. Below is my modified version.

Ingredients
2 tbsp (1/4 stick) butter or margarine
3-4 boneless, skinless chicken breasts, cut into bite sized pieces
1 medium onion, roughly chopped
2 cans (4oz) mushrooms, drained
1 cup sour cream
1 cup shredded cheddar cheese, divided
1 tbsp Mrs Dash chicken seasoning
1/2 box corn bread mix, prepared as directed*

*I use the remaining 1/2 of the corn bread mix to make muffins. I felt the casserole was too corn-bread-y with the entire box added and the chicken and other great flavors were a bit lost because of it.

Directions
Preheat oven to 425 F. Grease 9" square baking pan and set aside.

Melt butter in large skillet, cook chicken and onion until chicken is no longer pink and onion is transparent. Stir in sour cream, mushrooms, 1/2 cup cheddar cheese and seasoning. Remove from heat and set aside.

Pour 1/2 of the prepared corn bread mix into pan. Top with chicken mixture and bake in preheated oven 15 minutes. Sprinkle remaining 1/2 cup cheddar cheese on top and bake for another 25 minutes or until top is lightly browned. Let stand 10 minutes before serving.