For a meatier casserole, add in some cooked bacon pieces or chopped ham. 2. For a vegetarian version of this dish, ditch the sausage and add in some mushrooms which will provide a hearty flavor and meaty texture to the casserole. 3. Make a cheesy gravy by including shredded cheese in the mix - preferably cheese that you grate from a block of cheese and a choice of cheese that melts well. 4. I’ve kept the seasoning very simple in this biscuit and gravy casserole. Feel free to include some of your favorite spices or seasoning as a way to adapt this dish.