In a large pot, melt 4 tablespoons of unsalted butter over medium heat until foamy. Add 1 diced yellow onion, 1 diced celery stalk, and 1 diced green bell pepper. Sauté for 5 to 7 minutes until softened. Stir in 2 minced garlic cloves and cook for an additional minute.

Sprinkle ¼ cup of all-purpose flour over the sautéed vegetables in the pot. Stir continuously for about 2 minutes until the flour is cooked.

Gradually whisk in 4 cups of vegetable broth, then add 1 cup of heavy cream and ½ cup of half-and-half. Stir gently and heat until barely bubbling, about 5 minutes.

Bring the stew to a gentle simmer. Add 1 tablespoon of Old Bay seasoning, 2 teaspoons of Worcestershire sauce, and a splash of dry sherry. Cover and simmer for 15 minutes.

Carefully fold in 1 pound of picked-over lump crab meat and ¼ cup of chopped fresh parsley. Heat for an additional 5 minutes, stirring gently. Season with salt and black pepper to taste.