1 tablespoon olive oil 1 red bell pepper, cut into 1/4-inch rings 1 yellow bell pepper, cut into 1/4-inch rings 1 medium onion, cut into 1/4-inch slices 1 tablespoon Worcestershire sauce 1 teaspoon balsamic vinegar 4 sweet or hot Italian sausages (about 12 ounces total) 2 individual hero, hoagie, or grinder rolls (each about 7 inches long by 3 inches wide)
Bring a pot of water to a boil. Add sausages and boil for 10 to 15 minutes. Meanwhile, prepare grill.
In a small bowl drizzle 2 teaspoons oil over pepper rings, tossing to coat well. Secure each slice of onion horizontally with a wooden pick (to prevent separation into rings) and brush with remaining teaspoon oil.
Grill peppers and onions on an oiled rack set 5 to 6 inches over glowing coals 3 minutes on each side, or until tender. (Alternatively, peppers and onions may be grilled in batches in a hot well-seasoned ridged grill pan over moderately high heat.) Transfer peppers and onions to a bowl, discarding wooden picks, and toss with Worcestershire sauce and vinegar.
Grill sausages, turning them, until golden and just cooked through. Halve sausages lengthwise and rolls horizontally and grill, cut sides down, 1 minute, or until sausages are cooked through but still juicy and rolls are toasted lightly. Divide peppers and onions between rolls and top with sausages.
