Cook bacon until crisp and then drain.

Coarsely chop mushrooms and onions and then saute

Cook steaks until medium rare, or warm roast beef in a skillet until hot.

Cut the top off of the loaf about 3/4 of the way up then set aside. Using a spoon, hollow out the inside of the loaf. I save this bread to make croutons or bread pudding if using something other than rye.

Start building the sandwich by putting down a layer of bacon, followed by the steak/roast beef and then the cheese. Top with the onions and mushrooms and if there is any bacon remaining make a final layer on top.

Place the top of the loaf back on the filled sandwich then wrap the sandwich tightly in Saran wrap or butcher paper and optionally secure with string or twine. Place a weight on top of the sandwich to compress it and force the juice to permeate evenly. I use a large stockpot full of water. I leave the weight on for about 20 minutes but the time varies according to taste.