Prepare brussels: remove outer leaves, cut off stems, slice in half lengthwise. Spray inside of slow cooker with non stick spray.
Cook bacon and then dice with a sharp knife. Add brussels and all other ingredients into pot EXCEPT butter and parmesan cheese. Stir contents together.
Slice butter into smaller pats and lay on top of veggies. Close lid and cook for 3 hours on low. Lift lid and sprinkle on cheese. Cover just long enough for that to melt. Serve.
** If you want the bacon to stay crunchy then add it in with the parmesan cheese at the end instead.