French Onion Mushroom Casserole Recipe - It's like the best bowl of French Onion Soup you've ever had, only in the form of a casserole. It's the top of the soup -- the perfectly toasted French bread, the melting Swiss cheese, the caramelized onions, and all of the hearty, warm flavors of beef, garlic and mushrooms.
**ADD: Used dairy milk, and added chicken, nutritional yeast (mixed in egg batter, little less then cup?). Last ten minutes topped with Parmesan/provolone.** Creamy Broccoli and Mushroom Casserole - vegetarian, dairy-free, paleo