This is like a savory rice pudding, I prefer fresh sautéed mushrooms but canned will do fine, the rice will need to be cooked and completely cold before using, I sometimes like to add in steamed broccoli florets, if desired you may sprinkle some grated cheddar or mozzarella cheese on after baking and return to oven for a few minutes --- this may be doubled but you will need a very large casserole dish, a double recipe will not fit into a 13x9 dish --- prep time does not include cooking the rice.