Preheat your oven to 350 degrees.
In a medium saucepan, melt the butter over medium-high heat. While it is melting, cut the loaf of bread lengthwise and widthwise, WITHOUT cutting all the way to the bottom. (This is how you get your bread to pull.)
Add the mushrooms to melted butter and sauté until soft. Stuff the canals of the bread with half of the shredded cheese.
Using a spoon, add the sauteed mushrooms to the bread, evenly distributing throughout the slots in the bread.
Pour leftover butter mixture from the pan over the bread, and add remaining cheese.
Loosely cover the bread with aluminum foil, and bake for 15-20 minutes, or until bread has reached a golden brown.
Serve immediately.
