Finely chop yellow onion, bell pepper, celery, and garlic. Peel and devein shrimp, cutting into bite-sized pieces if desired. Cut fresh corn off the cob if using; measure frozen corn if not.

In a large Dutch oven, cook chopped bacon over medium heat until crispy, about 5–7 minutes. Drain excess grease, leaving about a tablespoon.

Add onion, bell pepper, and celery to the pot with bacon fat. Sauté for 5–6 minutes until soft. Stir in minced garlic and cook for an additional minute.

Pour sherry wine into the pot, stirring to deglaze and scrape up flavorful bits. Cook for 1-2 minutes.

Add butter until melted, then sprinkle flour over the mixture. Stir continuously for 3–4 minutes until roux is light golden-brown.

Slowly whisk in shrimp stock and water, ensuring no lumps. Bring to boil, then reduce to simmer for 20 minutes.

Add shrimp and corn to the pot, followed by heavy cream. Cook for an additional 5–7 minutes, until shrimp turns pink and opaque.

Adjust seasoning with salt, pepper, and Cajun seasoning. Serve hot, garnished with parsley and green onions.