Combine equal parts dashi, soy sauce, and mirin to create the soup base
Adjust seasoning to taste - add more soy sauce for saltier, more mirin for sweeter
Soak udon noodles in hot water to separate them, or microwave if preferred
Combine the soup base with the noodles
Top with green onions if desired
Optional: add bonito flakes, togarashi, tempura, and marinated egg for extra flavor