Grease sides of 9x13" casserole dish or slow cooker pot with butter.
Combine all ingredients except crispy fried onions in prepared dish and stir. Spread evenly in dish or pot.
Bake in 350 degree F oven for 25 minutes or slow cook on low for 3 hours.
Before serving, microwave crispy fried onions for 30 seconds and top casserole. Enjoy!