Preheat oven to 350°F. In a large pot, melt the butter over medium heat. Sauté the celery and onion until soft, then add in the flour, stirring until it is fully moistened. Slowly whisk in half-and-half. Add beer, lemon juice, Worcestershire, Old Bay or Cajun seasoning, bay leaf, and pepper and let mixture simmer for three to four minutes, stirring occasionally so it does not scorch. (Mixture will be thick, but the shrimp will release natural juices during cooking and thin the sauce.) Remove the bay leaf. Fold in the sliced potatoes, sausage, corn, and shrimp and transfer to a 13 x 9-inch shallow casserole pan lightly coated with cooking spray. Cover and bake for 30 to 40 minutes until potatoes are al dente. Uncover and cook an additional 20 minutes or until potatoes are easily pierced with a fork and casserole is bubbling. Let the casserole rest for 10 to 15 minutes before serving.
