In a large bowl, combine egg, cornstarch, flour, water, fish sauce, salt and pepper. Whisk together until well-blended and smooth.
Add fish, shallots and green onions. Gently stir to combine.
In a large skillet over medium heat, heat about 2-inch deep of oil to about 350 F. Using a large spoon, scoop about 2 to 3 tablespoons of the mixture and gently slide mixture into hot oil. Cook for about 3 to 4 minutes on each side or until golden brown and crisp. Do not overcrowd pan, cook in batches as necessary.
Using a slotted spoon, remove from pan and drain on a wire rack set over a baking sheet. For best results, serve immediately.