Crack the egg into a bowl, mix well, and strain through a sieve.

Mix water and matsutake broth mix in a bowl, then combine with the beaten egg.

Place shimeji mushrooms, ginkgo nuts, and shrimp into heatproof cups, then pour the egg mixture evenly into each cup.

Add water to a frying pan, filling it less than halfway up the cups, and heat until boiling. Place the cups in the pan, cover, and cook on medium heat for 1 minute.