Place the sausage links in a medium sauce pan. Fill with water until the links are covered 1 inch. Bring to a boil and let them boil for 5 minutes. (They will be parboiled, so they will not be cooked through. However, this will make them easier to slice.)

Use this time to cut the peppers and onions. Once the sausage is finished boiling, take them out of the water to cool so you can handle them to slice them.

Meanwhile, heat the olive oil in a medium skillet over medium high heat. Add the bell pepper and saute for about 5 minutes.

Next add the onions and season with salt and pepper. Saute for another 5 minutes and add the garlic. Cook for another 2 minutes.

While the peppers and onions are cooking, slice the sausage in 1/4 inch slice on a diagonal. (I usually use tongs to hold the links in place if they are still to hot to handle.)

Once the bell peppers, onions and garlic are finished cooking, remove them from the skillet and set aside.

Add the sausage to the skillet and cook until the pieces are cooked through.

Return the peppers, onions, and garlic to the pan along with the tomato sauce.  Cook until everything is heated through, about 3 minutes.

Top with Parmesan cheese and fresh parsley.