Boil chicken breast in boiling water for 10 minutes.

While the chicken is cooking, julienne cucumber, carrot, bell pepper, onion, and blanched shiitake mushrooms.

Shred the cooked chicken into bite-sized pieces.

Blanch rice noodles in boiling water for 30 seconds until slightly softened.

Heat a pan with oil and stir-fry onion and chili peppers until fragrant. Add shredded chicken, rice noodles, and seasonings (2 tbsp oyster sauce, 4 tbsp soy sauce, 3 tbsp sugar, 1/2 tbsp salt, 2 pinches black pepper, 1 tbsp sesame oil). Stir-fry until evenly mixed.

Arrange julienned vegetables in a circular pattern on a plate and place the stir-fried rice noodles in the center.

Mix 35g mustard, 1 tbsp soy sauce, 2 tbsp sugar, a pinch of salt, 2 tbsp vinegar, 1 tbsp sesame oil, and 2 tbsp water to create mustard sauce.