Very easy to make sandwich and you can save few bucks :). My husband described it this way, when you bite into it it has this softness from melted cheese, and crust form mushrooms and spinach.
Fry Mushrooms in frying pan with olive oil, until they have crust on outside. Sprinkle with salt and pepper to taste.
Grill or fry sausage on high heat until it has little crust.
Toast bread. Divide meat evenly among two sandwiches. Top with cheese and mushrooms. Sprinkle some parmesan cheese and add spinach.
Place it in George Foreman grill for about 1 minute, until cheese will melt little more. Or if you front have grill then just broil in oven for few minutes.