Prepare the Sauce: Heat olive oil in a saucepan over medium heat. Add minced garlic and sauté for 1 minute until fragrant. Stir in heavy cream and chicken broth. Simmer over medium-low heat for 10 minutes until slightly thickened.
Season the Chicken: Place chicken breasts in the slow cooker. Sprinkle with Italian seasoning, salt, and pepper. Top with sun-dried tomatoes.
Add the Sauce: Reduce heat to low and whisk in Parmesan cheese, adding 1/4 cup at a time until smooth. Pour the sauce over the chicken, ensuring even coverage.
Slow Cook: Cover and cook on High for 3-4 hours or Low for 6-8 hours until the chicken is tender.
Add Spinach: Remove the chicken and set it aside. Stir chopped spinach into the slow cooker, allowing it to wilt for a few minutes.
Serve: Return the chicken to the slow cooker, spooning sauce, spinach, and sun-dried tomatoes over the top. Serve warm.
Storage & Reheating Tips:
Refrigerate leftovers in an airtight container for up to 3-4 days.
Reheat in the microwave or on the stovetop until warm.
Freeze for up to 3 months; thaw in the fridge before reheating.