Preheat oven to 350ºF.

Put a large pot of water with a steamer basket on to boil.

Cut off and discard any tough outer leaves of artichokes; cut off and discard about an inch off the top of artichokes. Trim stems flush with bottom of artichoke and reserve for another use. If desired, snip off and discard barbed ends of remaining leaves. Gently pry artichokes open a bit, sprinkle with a little salt, drizzle with a little olive oil, and transfer to the steamer basket over boiling water. Cover and cook for 20 minutes. Transfer to a platter and set aside to cool.

Heat ½ cup remaining olive oil in a saucepan over medium heat. Add onions, corn, and bell pepper and cook, stirring often, until vegetables are softened, 10 to 12 minutes. Do not brown. Add crawfish and garlic and cook for 5 minutes. Mix together parsley, breadcrumbs, Parmesan cheese, Creole seasoning, and salt, pepper, and cayenne; taste for flavor. Stir into crawfish mixture, adding chicken stock if needed to moisten. Taste and adjust seasoning.

When artichokes are cool enough to handle, pull out and discard tightly curled center leaves. Use a spoon to scrape out and discard fuzzy choke from each artichoke. Spread leaves as far apart as possible and spoon mixture between leaves and in hollowed-out center.

Set artichokes on a rack in a deep baking dish. Add boiling water to just below rack. Drizzle artichokes with remaining olive oil and top each with a lemon slice. Cover with foil, then transfer to the oven and bake until browned, 45 minutes to 1 hour.