Cut the turnip leaves, leaving about 2 cm of stem. Clean the base thoroughly and peel the skin. Flatten the bottom for stability.

Cut off the top 1 cm of the turnip and scoop out the inside with a spoon.

Slice the shiitake mushroom thinly and cut the mitsuba into 1 cm pieces.

Remove the shrimp's vein if present.

In a bowl, beat the eggs until uniform. Add soy sauce, salt, and water, and mix well to create the egg mixture.

Place the shiitake slices inside the hollowed turnips and pour the egg mixture evenly into each turnip.

In a frying pan, combine sake, soy sauce, ginger, and water. Mix well.

Place the stuffed turnips gently into the pan. Bring to a boil, cover, and steam on low heat for 15 minutes.

Add the shrimp on top of the turnips, cover again, and steam for another 5 minutes.

Check the egg custard with a skewer; if it comes out clean, remove the turnips from the pan.

Add the cornstarch mixture to the remaining broth in the pan. Stir and heat for 1 minute until thickened.