Cook the Noodles: Bring a large pot of salted water to a boil.
Add the noodles and cook according to package directions until tender but not mushy (fresh noodles will only take a few minutes).
Drain, rinse with cool water to stop the cooking process, and set aside.
Prepare the Broth: In the same pot, bring the 6 cups (1440 ml) of water to a boil.
Stir in the soy sauce and ketchup.
Taste the broth and adjust seasoning with a little salt if needed, and a generous amount of black pepper.
Keep the broth at a gentle simmer.
Assemble and Serve: Divide the cooked noodles evenly among your serving bowls. Ladle the hot soy broth over the noodles.
Top each bowl with the cubed tofu, sliced scallions, and a sprinkle of chopped peanuts and fresh chile, if using.
Serve immediately!
Add More Veggies: Boost the nutritional value by wilting in some baby spinach or bok choy into the hot broth. Steamed broccoli, sliced mushrooms, or edamame also make fantastic additions.
Don't Skip the Garnish: Toppings are key! A drizzle of sesame oil, a squeeze of lime juice, or a sprinkle of toasted sesame seeds can add another layer of complexity and brightness to the finished dish.