Preheat the oven to 350°F.
In a large skillet, heat the olive oil over medium heat.
Add the diced bell pepper, onion, and celery. Sauté for about 5 minutes until softened.
Remove from heat and let cool slightly.
In a large bowl, combine the crab meat, breadcrumbs, sautéed vegetables, mayonnaise, green onions, Dijon mustard, Worcestershire sauce, Cajun seasoning, garlic powder, salt, black pepper, parsley, and lemon juice. Mix gently until well combined.
Stuff the crab shells with the mixture, pressing down slightly to pack it in.
Place the stuffed crab shells on a baking sheet.
Bake in the preheated oven for 25-30 minutes, or until the tops are golden brown and the stuffing is heated through.
Remove from the oven and let cool for a few minutes before serving.