Clean mushrooms and set aside. Flatten garlic and remove peel.
Combine all ingredients, except mushrooms and parsley in a dutch oven. Bring to a boil, then reduce heat and simmer 5 minutes. Add mushrroms and simmer uncovered for 10 minutes.
Remove from heat and let stand until slightly cool. Transfer mushrooms and marinade to a storage container. Cover and refrigerate until ready to serve.
Before serving, remove mushrooms from marinade and place in serving dish. GArnish with fresh parsley.