Mix all the sauce ingredients, including the juice and zest of 1 lemon in a small bowl and set aside for later.
Heat a wok on medium and add 2 tsp cooking oil. Add 3 tbsp dried baby shrimp (hoshi ebi) and 2 tbsp Japanese leek (naganegi) and fry for about 1 minute to flavor the oil.
Increase the heat to medium high and add 200 g shrimp and 100 g asparagus , and sprinkle with 1 pinch salt. Fry until the shrimp turn opaque, about 2-3 minutes.
Add 100 g bean sprouts and 50 g green cabbage and stir fry for 1-1 ½ minutes.
Push all the ingredients to one side and add 2 portions udon noodles to the empty space in the pan. Add a splash of water and gently separate the noodles as they steam.
Once the noodles are separated, pour the shio lemon sauce around the wok and stir fry everything together for 1-2 minutes.
Dish up and sprinkle with finely chopped green onions, ground black pepper and a drizzle of toasted sesame oil. Enjoy!
Notes
Use fresh or frozen udon for the best chewy texture. Vacuum-packed noodles should be loosened in hot water before stir-frying.If using dry udon, cook them 1-2 minutes less than the packaging states and wash them with cold water before use. Drizzle with oil if not using immediately.If you can't find hoshi ebi (dried baby shrimp), fry shrimp shells in oil for flavor - a technique that I used for my spicy seafood yaki udon recipe.Fridge: Transfer leftovers into an airtight container once cooled. Store in the refrigerator for up to 2 days.Meal Prep: Sauce only up to 3 days ahead.
Reheating: Use a skillet or wok over medium heat with 1-2 tablespoons of water to loosen the noodles and revive moisture. Stir frequently until steaming hot.