Preheat your oven to 350°F (175°C) and lightly grease a 9×9-inch baking dish.

Sauté chopped onion, celery, and bell pepper in a medium skillet over medium heat for 5–7 minutes until softened.

In a large mixing bowl, blend mayonnaise, sour cream, Dijon mustard, Worcestershire sauce, lemon juice, and egg until smooth.

Gently fold in lump crab meat and sautéed vegetables, being careful not to break up the crab too much.

Transfer the mixture into the prepared baking dish and spread evenly.

Sprinkle shredded cheese and breadcrumbs generously over the top.

Bake in the preheated oven for 25–30 minutes until golden brown and bubbling.

Let cool for 5–10 minutes before serving. Garnish with herbs or lemon if desired.