Heat a skillet over low heat with a drizzle of oil. Add the vegetables with a pinch of salt and sweat slowly for about 30 minutes, stirring occasionally, until they're soft, sweet, and lightly caramelized.

Set aside when done.

Meanwhile, thinly slice the chicken breast.

Heat a griddle or large skillet over medium-high heat and add the oil.

Add the chicken, season with salt, dried minced garlic, and Aleppo pepper, then chop it into small pieces with a spatula as it sears until browned and cooked through.

Pile the cooked peppers and onions over the chicken.

Cover everything with the shredded mozzarella.

Place the hoagie roll, cut-side down, over the cheese for a minute or two, allowing the bread to steam while the cheese melts.

Spread a little mayonnaise inside the steamed hoagie roll.

Add the shredded lettuce and sliced tomato. Carefully transfer the cheesy chicken mixture into the roll, and finish with a sprinkle of dried oregano.

Wrap the sandwich tightly in sandwich paper or foil. Let it rest for 1–2 minutes before slicing in half and serving.