Pat the chicken breasts dry with paper towel and season both sides with salt and pepper. Lightly coat with flour if using for extra browning.
Heat olive oil in a large skillet over medium-high heat. Add the chicken and cook for 4–5 minutes per side, or until golden brown and nearly cooked through. Remove from the pan and set aside.
In the same pan, reduce heat to medium and add a little more oil if needed. Sauté the garlic for 30–60 seconds until fragrant.
Stir in the sun-dried tomatoes and cook for another minute to release their flavour.
Pour in the chicken stock and scrape up any browned bits from the base of the pan.
Add the cream, Parmesan cheese, and Italian herbs. Stir well and bring to a gentle simmer.
Return the chicken to the pan and spoon the sauce over the top. Simmer for 5–8 minutes, or until the chicken is fully cooked and the sauce has thickened.
Stir through spinach (if using) and allow it to wilt into the sauce.
Taste and adjust seasoning with salt and pepper as needed.
Serve hot with pasta, mashed potatoes, rice, or crusty bread.