Melt butter in a pot over medium heat. Add diced onion, cook until translucent (5 minutes).
Add Old Bay seasoning, thyme, and flour. Cook for 1-2 minutes.
Add celery, carrot, potatoes, and corn. Pour in broth and white grape juice. Stir, bring to a boil, then simmer for 15-20 minutes.
Add seafood and simmer for 5-7 minutes.
Stir in heavy cream and simmer for 5 minutes. Season with salt, pepper, and garnish with parsley.