Cut peppers into strips, 2 cups each.
Prick each sausage in several places with fork
and place in large skillet with cover.
Add water to about ¼" depth and bring to boil.
Cover, reduce heat and cook 15 min.
Uncover; drain off fat and water. Raist heat
and cook sausages, turning often, until browned.
Push to one side. Add olive oil, onion, mushrooms,
and peppers. Mix to coat well with oil, then
cover and cook, stirring occasionally, 15 min.
Slit each roll lengthwise thru top but not cutting
right through. Spread cut surfaces with spicy mustard,
pressing soft insides down to make room for filling.
Fill each roll with 2 sausages, end to end, and top
with cooked vegetables. Serve at once. Serves 6.