Make the tempura batter

• Whisk the egg with the ice water in a bowl.
• Sift in the flour and cornstarch and stir briefly; the batter should stay lumpy and cold.

Prepare the sauce

• Bring the dashi, soy sauce, mirin and sugar to a simmer in a saucepan.
• Keep warm over low heat.

Heat the frying oil

• Pour the vegetable oil into a deep fryer or heavy pot and heat to 175 °C.

Fry the chicken

• Dip the chicken pieces in the batter, letting the excess drip off.
• Deep fry in batches until golden and cooked through, then drain.

Fry the eggs

• Crack the eggs into the batter and coat them gently.
• Lower them into the oil and fry until the coating is crisp and golden, then drain.

Assemble the bowls

• Divide the warm rice between bowls.
• Top with the fried chicken and tempura egg, spoon over the sauce and scatter with scallions.