Take the large yellow onion, remove the skin and slice into ¼ inch thick slices. Wash the bell peppers. Remove the tops and seeds and cut into long strips approximately ¼ inch thick. Place peppers and onions aside.
Heat a 10-12 inch skillet on medium-high heat.
Lay the sausage in the pan with plenty of space in between.
Add about a cup of water. You are looking for the water to come up about one quarter of the way up the sausage.
Bring the water to a simmer, and cover the pan with a lid. Simmer for 8 minutes with the lid on .
Remove the lid and drain off the excess water.
Return the pan to the stove and leave the heat on medium. Brown the sausage for 3 minutes. Turn the sausage and brown the other side. You will notice the fats that rendered out of the sausage are browning on the pan as well. Don’t panic! That is going to be great flavor for the onions and peppers.
Once the sausage is brown on both sides remove from the pan and set aside.
Add 1 Tablespoon of olive to the pan and keep on medium/low heat.
Add sliced onions and peppers to the pan. Stir to make sure that the onions and peppers are coated with olive oil.
Add the salt and pepper to the peppers and onions and let them cook. Every few minutes move them around the pan to make sure they aren't burning and that you are getting all of the vegetables close to the heat.
The onions should cook until they are translucent and soft, and the peppers should be soft but not so cooked that they lose their color. Luckily peppers tend to take longer to cook than onions so you can throw everything in together and they should be ready at the same time.
When the onions look just about done add the red wine vinegar.
Take your cooked sausage links and cut into 2 inch pieces. The sausage may be a touch under done in the center at this point and it is fine. Return the sausage to the pan and toss together with the peppers and onions. Continue cooking until all of the sausage pieces are cooked through.
Sausage is cooked when the internal temperature reaches 165°.
Serve Italian Sausage and Peppers with Pasta, Mashed Potatoes, or on with a great loaf of bread.