In a small pot, bring 2 cups of water to a boil. Add the noodles and cook for 1 minute by stirring until separated. Drain well and transfer to a serving bowl.
Meanwhile, heat a frying pan over medium heat and coat with the oil. Cook the tomato and asparagus until brown. Season with salt and pepper. Transfer the vegetables onto the noodles.
In the same frying pan, add 1 1/4 cup of water and the soup base. Mix well and bring to a boil.
In a small bowl crack the egg and beat with chopsticks. Then, pour into the boiling soup. Turn down the heat to medium. Cook until the egg is set.
Pour the soup and egg over the udon in the serving bowl. Enjoy!