Cut the cores from the sprouts and discard. Peel off the leaves, reserving them, and discard or thinly slice the tight, innermost heads. Heat a sauté pan and fry the bacon until crisp; remove to paper towel to drain. Pour all but a tablespoon of fat from the pan. Add the butter, to melt. Toss the leaves in, and sauté until tender, 15 to 20 minutes. Season, crumble over the bacon, and serve.