Season chicken with salt and pepper and place into slow cooker. Add in Marsala wine, mushrooms, and minced garlic into slow cooker.
2
Cook on low for 4-5 hours or on high for 2-3 hours.
3
Pull out chicken and place on a plate. Combine chicken broth and cornstarch. Stir in the broth/cornstarch mixture into slow cooker and put the chicken back into the slow cooker. Turn slow cooker on high for 30 minutes and cook until sauce thickens.