Wipe excess oil from the fried tofu with a paper towel and cut it diagonally in half. In a small pot, mix the seasoning ingredients for fried tofu and add the tofu. Heat over medium heat until boiling, then turn to low heat and simmer for 5 minutes.

Slice the green onion into small pieces.

Boil a large pot of water and add the soba noodles. Stir gently to loosen them. Once boiling again, reduce to low heat and cook according to the package instructions. Drain the noodles.

In a separate pot, mix the soup base ingredients and heat over medium heat until boiling. Turn off the heat.