Peel the shrimp and remove the vein along the back.
Thinly slice the onion, carrot, and green onion.
Heat cooking oil in a pan and sauté the onion and carrot.
Add the shrimp and cook until done.
Season with soy sauce, mirin, water, and pepper.
Add cornstarch slurry to adjust the thickness.
Spoon the cooked ingredients over the rice to serve.