Heat neutral oil and sesame oil in a large pot over medium heat. Add the onion and cook for 5 minutes. Add the garlic and ginger and cook for 1 minute until fragrant.

Add the chopped beets and cook 3–4 minutes. Season with salt and pepper.

Pour in stock or water and bring to a boil. Reduce heat and add soy sauce, dashi, and mirin and simmer for 30–40 minutes until the beets are soft. Note: If using small-diced beets, skip the next two steps.

Use an immersion blender to blend until mostly smooth. You can skip this, but I like to get out as much beet flavor as possible. You can also blend until completely smooth and skip the straining step below.

Place a fine-mesh sieve over a large bowl and pour the broth through the sieve. Discard solids and rinse out the sieve (you'll need it for the noodles). Keep warm.

Wipe out the pot used to make the beet broth and fill it with water. Bring to a boil. Add the eggs and boil for 7 minutes. Use a ladle to remove them and transfer to an ice bath. Keep the water boiling.

Add the noodles to the water and cook according to package instructions. Drain and set divide between 4 bowls.

Pour the warm beet broth over each bowl of noodles. Cut the eggs in half and place on each bowl. Garnish with scallions or microgreens and a sprinkle of salt. Enjoy!