In a large bowl, combine egg, cornstarch, flour, water, fish sauce, salt, and pepper. Whisk together until well-blended and smooth.
Add annatto powder and stir until dispersed and batter is lightly colored.
Add bean sprouts, carrots, and shallots and gently stir to combine.
In a large skillet over medium heat, heat about 2 inches deep of oil.
On a large spoon, place about 2 to 3 tablespoons of the ukoy mixture and press 1 to 2 shrimps on top.
Gently slide mixture into the hot oil and cook for about 3 to 4 minutes on each side or until golden brown and crisp.
With a slotted spoon, remove from heat and drain on a wire rack set over a baking sheet. Serve immediately with spicy vinegar dip.