Slow-Cooker Italian Sausage and Peppers on a Bun

I love Italian sausage in or with just about anything.  Especially some cheese tortellini and red sauce.  But, truth be told, I think that I just may love it this way the best.  The flavors are all so bright and distinct from the sausage to the peppers and then they are all merried together by this wonderful zippy sauce.  And then to top it off on a really delicious soft warm hoagie roll is next to bliss if you ask me.  Honest to god, it really is a party in your mouth.

1 lb. (about 5) mild Italian sausage links
1/2 cup of water
1 T. of extra virgin olive oil
1 large yellow onion (sliced)
2 medium green sweet peppers (cored and sliced)
1 cup or so of baby portabella mushrooms (sliced)
sea salt and fresh cracked pepper
1 garlic clove (minced)
1/4 cup of Italian salad dressing
2 T. of coarse ground Dijon mustard
5 hoagie buns (splurge on these and get the fresh ones from your markets bakery)

-In a large saucepan, over medium-high heat, brown your sausage well on all sides.  Add in the water, bring to a boil, reduce heat, cover and simmer for about 5 more minutes to cook them throughout the center.  Plate the sausages and set aside; drain pan.  Return the same pan (with all the good stuff still stuck to it-that's flavor) back to your stove top and heat it back up to a medium heat.  Toss in your e.v.o. and once you can smell it, then you are ready to add in the onion, peppers and mushrooms.  Give them a nice healthy sprinkle of salt and pepper and saute them until they are soft;  add in the garlic now.  Once you can smell the garlic, stir in the Italian salad dressing and the Dijon mustard.  Place your sausages back in the pan and bring all of this to a slight boil; reduce the heat.  Either transfer to your slow-cooker set to go Low and slow until dinner or you can serve them at this point (they are so much more tender after being in the slow-cooker for a few hours though).  Serve on a warm toasted hoagie bun.  Serves 4-5.  Enjoy!