Preheat the oven to 375 degrees.
Boil pasta according to directions.
Drain and rinse with cold water. Set aside.
In a large skillet brown the sausage. Break the sausage apart as it cooks.
When the sausage is brown, remove it from the skillet and allow it to drain on a paper towel.
Add the onions and mushrooms to the skillet and saute them, then add the sausage back into the skillet.
Now, add the pasta sauce and ½ a cup of cheese.
Stir.
Add pepper rings and stir.
Add the pasta and stir.
Top with shredded mozzarella cheese and pepperoni.
Place the skillet into the stove and allow to bake until the cheese is melted.
Serve immediately.