Step 1: Season Chicken with a blend of garlic salt, Italian seasoning, paprika, and black pepper.
Step 2: Sear Chicken. In a large skillet over medium-high heat, melt a knob of butter. Add the seasoned chicken breasts and sear them briefly (about 2-3 minutes) on each side, just to get a nice color.
Step 3: Assemble. Place the seared chicken breasts into your slow cooker. Top them with sliced mushrooms and minced garlic. Pour the marsala wine around the chicken in the slow cooker.
Step 4: Slow Cook to Perfection. Cover the slow cooker and let the chicken cook low and slow for 4-6 hours on low or 3-4 hours on high, until it's fall-apart tender.
Step 5: Thicken the Sauce. Once the chicken is cooked through, remove it from the slow cooker. In a small bowl, whisk together some water and cornstarch to make a slurry. Whisk this into the cooking liquid in the slow cooker to thicken it up. Let it cook for a few minutes to activate.
Step 6: Finish. Stir in some heavy cream to make the sauce extra rich and creamy.
Step 8: Serve & Enjoy. Add the chicken back to the slow cooker and spoon the luscious marsala sauce over the top. Serve your copycat Olive Garden chicken over pasta, mashed potatoes, or with a fresh salad on the side. Enjoy!