01 - Lightly grease the inside of the slow cooker with olive oil or nonstick cooking spray to prevent sticking.
02 - In a small bowl, whisk together the minced garlic, grated Parmesan cheese, chicken broth, heavy cream, olive oil, Italian herbs, paprika, salt, and black pepper until well combined.
03 - Arrange the halved baby potatoes and diced onion in an even layer at the bottom of the prepared slow cooker.
04 - Place the chicken breasts on top of the vegetable layer in a single, even arrangement.
05 - Pour the prepared garlic Parmesan sauce evenly over the chicken and potatoes, ensuring everything is well coated.
06 - Cover and cook on high heat for 4 hours or on low heat for 7 hours, until the chicken is fully cooked through (internal temperature reaches 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 completely.
08 - Remove the lid and garnish the dish with chopped fresh parsley and additional grated Parmesan cheese before serving.