small shrimp (shelled and deveined, or crawfish tails, shelled)
vegetable oil (for frying)
Combine all dry ingredients. Whisk in the eggs, butter and beer until smooth. Refrigerate at least 3 hours to give the gluten in the flour a chance to expand. Whisk again before using.
In a deep skillet or wok heat 1-1/2 inches of oil to 350F. Pat the shrimp dry, then dip in the batter. Drop some of the shrimp in the oil, but don't crowd, and fry until golden brown, turning once, about 2 minutes total. Drain well on paper towels and keep warm while frying the remaining shrimp. Be sure the oil returns to 350F before frying the next batch. Continue until all the shrimp are fried.
Preparation time does not include refrigeration time.