Step 1

Wash the zucchinis thoroughly. Cut them in half lengthwise, and then slice them into pieces about 3-4 cm long. Make two deep cuts into each side of the zucchini slices with a knife. A helpful tip: place wooden chopsticks on either side of the zucchini slice while cutting to ensure even and consistent depth.

Step 2

In a large bowl, mix water and salt generously. Place the cut zucchini slices into the saltwater, ensuring the skin side is submerged. Let them salt for 30 minutes. This process softens the zucchini and draws out excess moisture, preventing them from losing their shape later.

Step 3

Prepare a steamer by filling the bottom with water and bringing it to a boil. Once steaming, carefully place the salted zucchini slices into the steamer. Steam for about 3-5 minutes, just until the zucchini is tender but still holds its shape; it should not be mushy. Once steamed, remove from heat and let them cool slightly.

Step 4

Finely julienne the carrot into very thin strips. Aim for a size that is easy for children to eat.

Step 5

Rehydrate the dried wood ear mushrooms by soaking them in lukewarm water until soft. Trim off the tough, woody base and finely julienne the mushrooms. Do the same for the shiitake mushroom. (If you only have one type of mushroom, that’s perfectly fine to use.)

Step 6

In a pan, add a very small amount of cooking oil. Stir-fry the julienned carrots and mushrooms separately over medium heat. Add a tiny pinch of salt (flavor salt is good here) to enhance their natural flavors. Cook briefly until they are just tender, avoiding overcooking so they don’t become too soft.

Step 7

Finely shred the beef. In a small bowl, combine the shredded beef with 1/2 Tbsp soy sauce, 1/2 tsp minced garlic, 1/2 tsp oligodang, 1 tsp mirin, and a pinch of black pepper. Mix well to marinate.

Step 8

Heat a pan with just a tiny bit of sesame oil over low heat. Add the marinated beef and stir-fry, gently separating the strands so they don’t clump together. Once the beef is fully cooked, remove from heat and let it cool.

Step 9

Beat the egg and cook it as a thin omelet, separating the yolk and white if desired for distinct colors. Once cooled, thinly julienne the egg omelet into fine strips.

Step 10

For the bell pepper, remove the seeds and thinly julienne the colorful outer skin. (This step is optional, but it adds beautiful visual appeal to the dish.)

Step 11

Ensure the steamed zucchini slices are completely cooled. This is important for the rolls to hold their shape nicely when filled.

Step 12

Carefully fill the slits in the cooled zucchini slices with the prepared ingredients: stir-fried beef, mushrooms, carrots, egg strips, and bell peppers. Arrange them colorfully and neatly, packing them in gently.

☆Making the Mustard Sauce: In a small bowl, combine 1/2 Tbsp mustard powder, 2 Tbsp vinegar, 3 Tbsp soy sauce, 1 Tbsp sugar, and 1/3 Tbsp sesame seeds. Whisk well until the mustard powder is completely dissolved and the sauce is smooth. This tangy mustard sauce is a perfect accompaniment.