Crack the eggs into a bowl and whisk. Add (A) and mix well.

Heat the oil in a frying pan over medium heat, then pour in the egg mixture. Stir gently 2-3 times, and when the edges start to set, gather the mixture in the centre to form a circle about 10 cm in diameter.

Place the omelette on a sheet of plastic wrap and shape it while still warm into a rectangle about 5 cm wide, 10 cm long, and 2 cm thick. Once it has cooled, cut it into 1 cm wide pieces.

In a pot, combine (B), chicken, and carrot. Heat over medium heat until the carrot is tender enough for a skewer to easily pass through. Add the shiitake mushrooms and leek, and continue to heat.

Boil a large pot of water in a separate pan and cook the udon according to the package instructions. Drain the noodles and place them in a serving bowl. Arrange the omelette, spinach, and the cooked ingredients from step 3 attractively on top, then pour the broth over everything.