Preheat oven to 350 degrees F. Lightly grease 4 (2-cup) oven safe bowls. Place bowls on a jelly roll pan.
In a large skillet, melt butter over medium heat. Add onion, celery, mushrooms and cook 6 to 8 minutes, or until vegetables are tender, stirring occasionally. Stir in flour and cook 2 minutes, stirring constantly. Stir in Creole seasoning, sherry and cheese. Stir in half-and-half, and cook 5 minutes, or until thickened. Remove from heat and add shrimp, scallops and crab. Spoon into prepared dish.
Spoon the Drop Buttermilk Biscuits evenly over each casserole. Bake for 20 minutes or until biscuits are golden.
In a medium bowl, combine baking mix, cornmeal, garlic powder and cheese. Stir in buttermilk just until dry ingredients are moistened.
Yields: 12 biscuits