I made this for the RSC #11 contest. This certainly isn't a low fat or diet friendly sandwich but it is very indulgent tasting. I grilled mine on my Foreman Grill so that I didn't have to use extra butter and plus I got the nifty grill mark lines :)
Saute shallots, mushrooms and bacon in the olive oil until the bacon is cooked through but not crispy and the shallots are softened.
Put the shredded cheese in a small bowl and sprinkle with cayenne pepper. Toss until all of the cheese is coated by the cayenne pepper.
Put half of the cheese mixture on one of the slices of bread.
Top cheese with the shallot, mushroom and bacon mixture and spread out so that it fully covers the bread and cheese.
Arrange the six tomato halves on the bread so that they form two parallel lines down the middle of the bread.
Put one spinach leaf on each corner.
Put the second half of the cheese mixture on top of the spinach and top with the second slice of bread.
Spray each side of the sandwich with butter flavored cooking spray and put onto a hot Foreman type grill and cook until the cheese is melted and the outside is golden (about 5 minutes) OR fry in a buttered pan as you would a traditional grill cheese sandwich.