Preheat oven to 400°. Lightly spray a 13×9-inch baking dish with nonstick spray. Combine shrimp, leeks, celery, 1 cup chicken broth, corn, bacon, wine, garlic, and Creole seasoning in prepared baking dish. Add 5 tablespoons butter, ¼ cup self-rising flour, and 1/4 cup buttermilk; stir until combined and set aside.

Whisk together remaining 2 cups self-rising flour, baking powder, and salt in a large bowl. Add 1 cup Cheddar cheese and 2 tablespoons green onions; toss to combine. Cut in remaining 5 tablespoons butter with a pastry blender until mixture resembles coarse crumbs. Make a well in the center of the flour mixture. Add remaining 1½ cup buttermilk. Stir with fork just until combined.

Using a 2-inch scoop (about 3 tablespoons), drop dough mixture on top of shrimp mixture to make 12 biscuits. Bake 35 minutes. Sprinkle with remaining ½ cup cheese; bake 5 to 10 minutes or until biscuits are golden brown and cheese is melted. Cool 5 to 10 minutes before serving. Garnish with green onion, if desired.