Chicken with Creamy Mushroom Sauce

chicken breasts

onion, finely chopped

garlic, crushed

cremini mushrooms, sliced

coconut milk (4.5 syns) (you can substitute with a ¼ cup of single cream or half and half in place of this, but syns will need to be adjusted)

chicken broth

wholegrain mustard (0.5 syns)

arrowroot powder, cornstarch or tapioca powder(1.5 syns)

Salt and black pepper

spray oil