Ebi Kimizushi (Prawn Sushi with Egg Yolk)
TO COOK PRAWNS: Leaving the shells of the prawns intact, insert the toothpicks along the inside curves to prevent curling.
Drop the prawn into ¾ pint of boiling water and cook briskly, uncovered, for about 3 minutes until pink and firm.
Drain in a sieve and cool quickly under cold running water.
Remove the toothpicks and peel the prawns, leaving the last section of shell and tail on each one.
De-vein the prawns by making a shallow incision across their tops with a small, sharp knife.
Lift out the vein.
Butterfly the prawns by cutting along their inner curves ¾ of the way through, spreading the open and flattening with a cleaver.
MARINADE: Put the vinegar, water, salt, sugar and MSG into a mixing bowl and stir together thoroughly.
Add the prawns, marinade at room temperature for 1 hour.
FILLING: Drop the egg yolks into a small saucepan and beat lightly with a fork.
Remove 2½ teaspoons of the yolks and set aside.
Add ¾ pintt of water to the remaining yolks, stir thoroughly, and cook over a moderate heat for 10 to 15 minutes until the yolks are firm and hard-boiled.
Drain them in a sieve, and mash them into a paste.
Beat the sugar, salt, salt, lemon juice, MSG, and the rest of the raw egg yolks and continue to beat.
Rub the mixture through a fine sieve.
TO ASSEMBLE AND SERVE Divide the seasoned egg filling into 6 equal parts and pack each part into the center of a prawn.
Seal the edges by pressing them together.
Serve at room temperature.