Preheat oven to 350°F. Carefully slice sourdough bread in both directions (about 2-inches apart) with a sharp serrated knife, being careful not to cut through the bottom of the loaf.
Take cheese slices, and place in between cuts in the bread. Then add bacon (you'll want to push the bacon down into the cuts of the bread.)
Mix together ranch dressing mix and butter. Drizzle butter mixture over bread.
Wrap in foil and place on a baking sheet; bake 15 minutes.
Unwrap foil, and continue to bake another 10 minutes, or until cheese is melted.