1. 1. Prepare the Chicken: Pat the chicken breasts or thighs dry with paper towels. Season both sides generously with salt and black pepper. This initial seasoning is crucial for building flavor from the start.

2. 2. Sear the Chicken (Optional but Recommended): In a large skillet, heat the olive oil over medium-high heat. Sear the chicken for 2-3 minutes per side until lightly browned. This step adds a beautiful depth of flavor and color, but if you’re truly short on time, you can skip it and place the raw chicken directly into the slow cooker.

3. 3. Saute Aromatics: Add the sliced mushrooms and chopped onion to the same skillet (or directly to the slow cooker if you skipped searing). Saute for 5-7 minutes until the mushrooms are softened and the onion is translucent. Stir in the minced garlic and cook for another minute until fragrant.

4. 4. Combine in Slow Cooker: Transfer the seared chicken (if using) and the sauteed mushroom and onion mixture to your slow cooker. Pour in the Marsala wine and chicken broth. Ensure the chicken is mostly submerged in the liquid.

5. 5. Slow Cook: Cover the slow cooker and cook on low for 6-8 hours or on high for 3-4 hours, until the chicken is very tender and easily shredded with a fork. The exact time may vary slightly depending on your slow cooker.

6. 6. Thicken the Sauce: Once the chicken is cooked, remove it from the slow cooker and set aside. In a small bowl, whisk together the cornstarch and cold water to create a slurry. Stir the slurry into the liquid in the slow cooker.

7. 7. Add Cream and Finish: Stir in the heavy cream. Cover and cook on high for an additional 15-20 minutes, or until the sauce has thickened to your desired consistency.

8. 8. Shred and Serve: Shred the cooked chicken using two forks or cut it into bite-sized pieces. Return the chicken to the slow cooker and stir to coat it in the creamy Marsala sauce. Garnish with fresh parsley, if desired, and serve hot.