Using a large skillet on a medium/high heat, add 1lb of sliced mushrooms and sprinkle with a little salt. Cook for about 5-7 minutes, or until golden brown color, stirring few times.
To the same skillet add 1 cup of Italian dressing, 1 diced onion and 1 sliced red pepper. Stir and bring it to a boil. Reduce the heat to medium heat, cook for 3 more minutes, stirring few times.