Halve baked a cooled potatoes lengthwise. Carefully scoop out most of the flesh and set aside. Place shells on a baking sheets. In a skillet, sauté onions, belle pepper, celery, and garlic in butter until soft. Add crawfish or shrimp; cook 2 minutes. Remove from heat. In a mixing bowl, combine sour cream, cheese, hot sauce, lemon juice, potato flesh, and crawfish or shrimp mixture. Mix well and spoon into potato shells. Sprinkle with Parmesan cheese. Bake at 350F for 25 minutes.