In a small bowl, combine the finely chopped lemon peel, minced garlic, onion powder, black pepper, and salt.
Place the chicken breasts in a shallow dish or resealable plastic bag. Rub the garlic and lemon peel mixture evenly over the chicken, coating it well. Let it marinate in the refrigerator for at least 30 minutes, or up to 4 hours for best results.
Heat the olive oil in a skillet over medium-high heat. Once hot, add the chicken breasts and cook for 5-6 minutes per side, or until they are cooked through and golden brown on the outside.
Remove the chicken from the skillet and let it rest for a few minutes.
Slice the chicken breasts and serve, garnished with chopped parsley if desired.