01 - Lightly grease the inside of the slow cooker with olive oil or nonstick spray to prevent sticking.
02 - In a small bowl, whisk together the garlic, Parmesan, chicken broth, heavy cream, olive oil, Italian herbs, paprika, salt, and pepper until well combined.
03 - Arrange the halved baby potatoes and diced onion in an even layer at the bottom of the slow cooker.
04 - Place the chicken breasts on top of the vegetable layer, ensuring they are not overlapping too much.
05 - Pour the Parmesan garlic sauce evenly over the chicken and vegetables, making sure to coat everything thoroughly.
06 - Cover and cook on high for 4 hours or on low for 7 hours, until the chicken reaches an internal temperature of 165°F and the potatoes are fork-tender.
07 - During the last 30 minutes of cooking, stir in the baby spinach and allow it to wilt in the hot mixture.
08 - Sprinkle with chopped fresh parsley and additional grated Parmesan before serving hot.