Using a sharp knife, slice each chicken breast in half horizontally, being careful not to slice it all the way through. Open the chicken like a book and place it between two pieces of plastic wrap. Pound the chicken to an even thickness and pat dry.
Combine the Italian seasoning, garlic powder, salt, MSG (if using), black pepper, and paprika together in a small bowl. Sprinkle the seasoning over the chicken, coating both sides.
Let the chicken sit for 30 minutes, or as long as overnight in a covered container in the refrigerator.
Heat the canola oil in a large cast-iron skillet over medium-high heat. Add the chicken breasts and cook for about 5 minutes on each side, until the chicken is browned and crispy and the internal temperature reaches 165°F. Transfer the chicken to a plate and pour the melted butter over the chicken.
While the chicken is resting, place the lemon halves cut-side down in the hot skillet until charred, about 3 minutes.
Squeeze the lemons over the chicken before serving and top with fresh parsley.
