Heat 2 tablespoons of olive oil and 2 tablespoons of unsalted butter in a large pan over medium-high heat.
Dredge the chicken breasts in finely crushed seasoned croutons, coating both sides.
Place two chicken breasts in the pan at a time and cook for 1 minute on medium-high heat, then reduce heat to medium-low.
Cook each breast for about 5-7 minutes, flipping halfway through, until the internal temperature reaches 160°F.
Remove and set aside.
Add more butter and oil to the pan, repeating the process with the remaining chicken.
Prepare the pesto sauce while the chicken is cooking.
Butter the inside of the hoagie rolls and sprinkle with garlic salt.
Broil the bread open-faced until golden and crispy.
Once the bread is ready, add a spoonful of marinara sauce to the bottom half of the rolls.
Place the cooked chicken on top of the sauce, cover with more marinara, and top with mozzarella cheese.
Broil the sandwich until the cheese is melted and bubbly, then finish with a sprinkle of parmesan and a smear of pesto.
Top with the other roll and enjoy