I made this to take for lunch this week. I divided the mushroom mixture among 4 dishes and then laid a slice of provolone on top of each. It reheated just fine in the microwave and the provolone melted perfectly. As I was cutting up the portobellos, I kept thinking that there was going to be way too much for 4 sandwiches but the portobellos cook down quite a lot. However, I did end up transferring the mixture from the frying pan that was overflowing to my dutch oven so that I could stir the mushrooms while they cooked. Absolutely delicious ... and I didn't miss the meat at all. I'm a new vegetarian and recipes like this make it so easy!