WOW, I really didn't have much hope for this meal but I decided to try it. Mushrooms are not my favorite and my husband really doesn't like them. But I have been trying to use them in different ways. This sandwich was a mega hit... The mustard adds an edge, the onions fried in balsamic vinegar and oil had a sweet taste, and the sauted mushrooms really added a texture along with a "buttery" & "meaty" flavor.. It was really very yummy.. I know lots of adjective. I was just really surprised. A picture will post tomorrow. ( I didn't use the Caesar sauce recipe that was listed with it though.) This is a very satisfying sandwich.