Prepare the shimeji mushrooms by trimming the base and separating them by hand. Thinly slice the onion and mince the garlic.

Clean the shrimp by removing the vein and pat dry. Prepare the squid by removing the innards, cutting the tentacles, and slicing the body into bite-sized pieces. Prepare the scallops as needed.

Heat half of the olive oil in a pot and sauté the shrimp, squid, and scallops briefly. Add sake, cover, and cook until done. Remove from the pot.

In the same pot, add the remaining olive oil, mushrooms, onion, and garlic. Sauté over medium-low heat for 6–7 minutes. Add water and bring to a boil.

Turn off the heat, add curry roux, and stir until dissolved. Return the seafood to the pot and simmer on low heat until thickened.