In a bowl, mix together all-purpose flour, cornstarch, and baking powder.

In a separate bowl, whisk the large egg and cold water together until frothy.

Gradually pour the wet mixture into the dry ingredients, stirring gently until just combined.

In a deep fryer or heavy pot, heat vegetable oil to 350°F (175°C).

Take the tail-on shrimp and dip them into the batter, letting the excess drip off.

Carefully place the battered shrimp into the hot oil in batches. Fry until golden brown, approximately 2-3 minutes per side.

Once fried, drain the shrimp on paper towels to remove excess oil. Serve immediately with your choice of tempura dipping sauce and yum yum sauce.