Creating Slow Cooker Creamy Chicken is straightforward if you follow these simple steps:

1. Prepare the Slow Cooker: Start by greasing the insert of your slow cooker with a little olive oil to prevent sticking.
2. Sauté Aromatics: In a skillet, heat the olive oil over medium heat. Add diced onions and minced garlic, cooking until fragrant and softened, about 2-3 minutes.
3. Layer Ingredients: Place the chicken breasts in the bottom of the slow cooker. Season with salt, black pepper, Italian seasoning, and red pepper flakes (if using).
4. Add Vegetables: Layer the sautéed onions, garlic, sliced mushrooms, and spinach on top of the chicken.
5. Pour in Broth: Add the chicken broth to the slow cooker, ensuring the chicken is covered as much as possible.
6. Cook: Cover and cook on low for 6-8 hours or on high for 4-5 hours until the chicken is fully cooked and tender.
7. Add Cream and Cheese: Once cooked, remove the chicken and whisk in the heavy cream and grated Parmesan cheese into the slow cooker. Stir until the sauce is creamy and well combined.
8. Return Chicken: Shred the chicken with two forks and return it to the sauce, mixing well to combine everything.
9. Taste and Adjust Seasoning: Give the sauce a quick taste and adjust seasoning if needed.
10. Keep Warm: Set the slow cooker to the warm setting while you prepare your sides.

These easy-to-follow steps will guide you through making an incredibly delicious Slow Cooker Creamy Chicken that everyone will enjoy!