Layer trimmed green beans in bottom of slow cooker.
In mixing bowl, whisk together mushroom soup, milk, sour cream, and seasonings until smooth.
Pour cream mixture over green beans.
Sprinkle with chopped onion, crumbled bacon, and cheese.
Cover and cook on LOW 4-5 hours until beans are tender.
In final 30 minutes, add French fried onions on top.
Top with extra cheese and let melt.
Garnish with additional bacon and parsley if desired.