Heat vegetable oil in a deep skillet or Dutch oven to 350°F, keeping the temperature steady for even frying. Set up three bowls with flour in the first, whisked eggs and milk in the second, and bread crumbs mixed with salt, pepper, and garlic powder in the third.

Dredge each chicken breast in flour, shaking off the excess, then dip into the egg wash before pressing firmly into the bread crumbs to fully coat. Make sure the coating is even and well adhered for maximum crunch.

Fry the breaded chicken in batches for 4–5 minutes per side until golden brown and crispy. Cook until the internal temperature reaches 165°F, then transfer to a wire rack to rest while you prepare the rolls.

Mix softened butter with parsley and garlic powder, then spread evenly on the cut sides of the sandwich rolls. Toast in a skillet over medium heat or in a 375°F oven for 3–5 minutes until lightly golden and fragrant.

Warm the marinara sauce in a saucepan over medium heat until gently simmering. Place the crispy chicken on the toasted rolls, spoon marinara generously over the top, and add slices of white American cheese.

Broil the open-faced sandwiches for 1–2 minutes until the cheese is melted and bubbly. Top with fresh basil, close the sandwiches, and serve immediately while hot and crispy.