Begin by seasoning your boneless, skinless chicken breasts generously with salt and pepper on both sides.

In a large skillet, heat a tablespoon of olive oil over medium heat. Add minced garlic and sauté for about one minute.

In a mixing bowl, combine soy sauce, chicken broth, and Marsala wine. Whisk until well blended.

Place the seasoned chicken breasts at the bottom of your crockpot. Pour the prepared sauce over the chicken, then top with sliced mushrooms.

Cover the crockpot and set it to low heat, cooking for about 6 hours, or on high for 3 hours.

Once cooked, gently stir in the heavy cream into the sauce right before serving.