Trim the stems of the shiitake mushrooms. Separate the caps and stems, then slice them thinly. Trim the root of the enoki mushrooms and cut them into thirds. Separate the root parts into bite-sized pieces.

Remove the seed from the umeboshi and mash it with a knife to create ume paste.

Place the shiitake and enoki mushrooms in a microwave-safe container with 1 tbsp of water. Cover loosely with plastic wrap and microwave at 600W for 2 minutes. Drain the excess water.