Finely chop onion, bell pepper, celery, green onions, and parsley. Mince garlic. Remove corn kernels from the cob. Chop bacon into small pieces. Peel and devein shrimp, pat dry, and season with cajun seasoning.

Heat a large dutch oven over medium heat and add chopped bacon. Cook for about 8 minutes until bacon is starting to crisp, stirring occasionally. Drain all but about 1 tablespoon of bacon grease.

Turn heat to medium-low and add onion, bell pepper, and celery. Sauté for about 5 minutes until vegetables are softening. Add garlic and cook for about 1 minute.

Add sherry to deglaze the pot, scraping up any browned bits. Simmer for 1-2 minutes.

Add butter to the pot to melt. Once melted, sprinkle flour over the mixture. Cook for about 5 minutes, stirring, until flour has slightly darkened.

Whisk in shrimp stock gradually until incorporated without lumps. Add water and mix in. Add half of the parsley and green onions. Bring to a boil, then reduce heat to low simmer for 20 minutes.

Stir occasionally to make sure it doesn't stick. Skim off any fat or foam that rises.

Add seasoned shrimp, corn, and heavy cream. Add remaining parsley and green onions, then bring back to a simmer. Cook for 5 minutes until shrimp are cooked through.

Taste and adjust seasoning with more salt, pepper, or cajun seasoning as needed.

Serve hot, optionally garnished with parsley and/or green onions.