A combination of sauteed onions, bell peppers, and mushrooms makes a tasty topping for this chicken cutlet sandwich, assembled on half a baguette.
In a large skillet, heat 1 teaspoon oil over medium. Add onion, bell pepper, mushrooms, and oregano. Season with salt and pepper. Cook, stirring frequently, until onion and bell pepper are tender, about 12 minutes. Transfer mixture to a medium bowl and stir in vinegar; tent with foil to keep warm.
Add 1 teaspoon oil to skillet. Season chicken on both sides with salt and pepper and pinch of cayenne. Cook until golden brown on one side, about 3 minutes. Flip and cook until chicken is cooked through, about 1 minute more.
Spread mayonnaise on inside of bread. Assemble sandwich with vegetables, chicken, and lettuce. Cut in half crosswise to serve.
Scooping out the breadmakes the sandwichlighter. Turn the excessbread into breadcrumbs.