- Cook ziti according to directions; drain.
- In a saucepan, brown sausage.
- Remove to paper towels to drain.
- Melt the butter in skillet and saute mushroom, green pepper and onion until just tender.
- Blend flour into the vegetable mixture, stirring well until blended and bubbly.
- Gradually add milk and cook over medium low heat, stirring constantly, until mixture begins to boil.
- Continue to cook and stir for 1 minute.
- Blend in 1 cup of the cheddar cheese, Parmesan and pepper, stirring until cheeses are melted and mixture is smooth.
- Stir hot, cooked ziti and sausage into vegetable cheese sauce.
- Pour into greased 2-3 qt. casserole dish.
- Top with remaining cup of cheddar cheese.
- Bake at 350 °F for 30 minutes or until hot and bubbly.