If the chicken breasts are thick, pound them to an even thickness of about 1/2 to 3/4 inch. Pat them dry, then season with about 3/4 teaspoon of the salt, the black pepper, and the rosemary.

Heat 1 tablespoon olive oil and 1 tablespoon butter in a large skillet over medium-high heat. Add the seasoned chicken and cook for about 4–6 minutes per side, depending on thickness, until browned and the center reaches 165°F.

Transfer the cooked chicken to a plate and keep the browned bits in the skillet. Add the remaining olive oil and butter, then arrange the mushrooms in a single layer and cook for 5–7 minutes, stirring occasionally, until browned and their moisture has evaporated.

Add the minced garlic to the mushrooms and cook for about 30 seconds, stirring constantly so it becomes fragrant without burning. Pour in the chicken broth and white wine, scraping up the browned bits from the bottom of the skillet.

Simmer the liquid for 3–5 minutes, or until it has reduced slightly and looks like a light sauce. Stir in the lemon juice, taste carefully, and adjust only if needed with the remaining salt.

Return the chicken and any accumulated juices to the skillet. Simmer for 1–2 minutes while spooning the rosemary mushroom sauce over the chicken, then garnish with parsley and serve immediately.