1. Shell the shrimp. Then cut them in half lengthwise with a small, sharp knife and lift out the black or white intestinal vein with the point of the knife. Wash the shrimp under cold running water and pat them completely dry with paper towels.
2. With a wire whisk or table fork, mix the flour and water together in a deep bowl. Break in the eggs and continue beating until the batter is smooth. Stir in the shrimp, scallions, carrots, celery, garlic, coriander, cumin, salt and white pepper.
3. Pour the oil into a heavy 12-inch skillet. The oil should be about 1 inch deep; if necessary, add more. Heat the oil until it is very hot but not smoking. For each bahwan, ladle in about 2 tablespoons of the shrimp mixture.
4. Cook 3 or 4 cakes at a time, leaving enough space between them so that they can spread into 3-inch rounds. Turning them carefully with a slotted spatula, fry the bahwan for about 2 minutes on each side, or until they are crisp and golden brown.
5. As they brown, transfer the cakes to paper towels to drain. Serve them while they are still warm, arranged attractively on a heated platter.
