4 (4-ounce) spicy Italian sausages
1 large red onion, cut crosswise into 4 (1/2- inch- thick) slices
1 yellow bell pepper, cut into 1/2-inch slices
1 poblano chile, cut into 1/2-inch slices
1 tablespoon extra- virgin olive oil
1/2 cup torn fresh herbs, such as basil and oregano
1 teaspoon kosher salt
1/2 teaspoon black pepper
4 hoagie rolls, split
8 (3/4-ounce) provolone cheese slices (optional)
Heat a camping stove or grill to medium-high (about 375° to 400°F), or fit a grilling grate over the direct heat of glowing embers. Place the sausages, onion slices, bell pepper slices, and poblano slices on the grilling grate directly over the heat source; grill, turning occasionally, until charred, about 10 minutes.
Tear or cut 4 (18-inch) squares of aluminum foil. Divide the sausages and vegetables evenly among the foil squares. Drizzle evenly with the oil; sprinkle evenly with the herbs, salt, and black pepper. Toss to coat. Gather the edges of each foil sheet into a packet, and crimp to seal. Place the packets on the grill grate; grill until the sausages are cooked through, 10 to 15 minutes.
Top the bottom half of each roll with 2 provolone slices, if desired. Divide the sausages and vegetable mixture evenly among the rolls. Top with the top halves of rolls.