Slice the onion thinly. Mince the garlic and ginger.

Defrost the seafood mix. In a bowl, mix oysters with cornstarch and gently wash with water until clear. Pat dry with paper towels.

Heat 1 tbsp of salad oil in a pan over medium heat. Stir-fry the seafood mix and oysters quickly, add sake, cover, and steam for 1–2 minutes. Remove from pan.

In the same pan, add the remaining salad oil, garlic, and ginger. Sauté over low heat until fragrant. Add onion and cook until softened. Add water and bring to a boil, then cover and simmer for 5 minutes.

Turn off the heat, add curry roux, and stir until dissolved. Return the oysters and seafood mix to the pan and simmer for another 1–2 minutes.