01 - Lightly grease the inside of the slow cooker with olive oil or nonstick cooking spray.
02 - In a small bowl, whisk together the minced garlic, grated Parmesan, chicken broth, heavy cream, olive oil, Italian herbs, paprika, salt, and black pepper until well combined.
03 - Place the halved baby potatoes and diced onion in an even layer at the bottom of the slow cooker.
04 - Arrange the chicken breasts on top of the vegetable layer.
05 - Pour the garlic Parmesan sauce evenly over the chicken and potatoes, ensuring all pieces are coated.
06 - Cover and cook on high setting for 4 hours or on low setting for 7 hours, until the chicken reaches an internal temperature of 165°F and the potatoes are fork-tender.
07 - If using, stir in the baby spinach during the last 30 minutes of cooking and allow it to wilt.
08 - Sprinkle with chopped fresh parsley and additional grated Parmesan cheese before serving.