Bring a large pot of water to a boil with a pinch of salt. Meanwhile, peel the ginger with a spoon,then mince or grate along with the garlic. Thinly slice the scallions, keeping white and green parts separate. Trim and discard the root and tops of the leek, then halve and thinly slice. Rinse under water, tossing, to remove any silt. Drain.

Heat 1 tablespoon olive oil in a large pan over medium heat. Add the shiitakes and cook, tossing, 5-6 minutes, until soft and golden brown. Set aside.

In the same pan, heat 1/2 tablespoon olive oil over medium heat. Add the leek to the pan and cook, tossing, 4-5 minutes, until softened. Add the porcini powder, scallion whites, ginger, and garlic to the pot and cook, stirring, another 30 seconds. Season with salt and pepper.

Add 5 cups water, soy sauce, and stock concentrates to the pot and bring to a simmer for 10 minutes. Taste and season with salt, if necessary.

Meanwhile, add the udon to the boiling water and cook 9-10 minutes, until al dente. Drain and divide between two bowls.

Top the udon with the broth, then arrange the shiitakes and seaweed along the sides of the bowl. Garnish with scallion greens and enjoy!