Bring the soy sauce, mirin and sugar to boil in a saucepan.
Add the minced garlic and ginger. Reduce by half then add the corn-starch diluted in a little water (optional).
Cooking the shrimps:
Shell the shrimps keeping the heads and tails.
Heat the griddle (plancha).
Cover the shrimps with a little teriyaki sauce and place them on the griddle for 1 to 2 minutes on each side.
Serve the shrimps with the rest of the teriyaki sauce.
Chef’s tip:
You can marinate the shrimps for 15 minutes in teriyaki sauce before cooking them. You can add a pinch of Espelette pepper to the shrimps before cooking them, and they will be even better.