Pat the chicken breasts dry with paper towels. If they are thick, pound them to an even thickness.
In a small bowl, combine the garlic powder, onion powder, salt, black pepper, and chopped rosemary.
Rub the chicken breasts with olive oil, then coat both sides evenly with the seasoning mixture.
Heat a large skillet over medium-high heat.
Add the chicken breasts and cook for 5 to 6 minutes per side until golden brown.
Reduce the heat to medium. Add the butter and minced garlic to the skillet. Cook for about 1 minute until fragrant, then spoon the garlic butter over the chicken.
Drizzle with lemon juice, if using, and continue cooking until the chicken reaches an internal temperature of 165°F (74°C).
Remove the chicken from the skillet and let it rest for 5 minutes before serving.
Garnish with fresh parsley and serve warm.