Wrap the tofu in a paper towel, place it in a microwave-safe container, and heat at 600W for 2 minutes. Let it cool. Roughly crush the roasted walnuts by hand.

Boil water in a pot, add a pinch of salt (not listed in ingredients), and blanch the watercress briefly. Rinse in cold water, squeeze out excess water, and cut into 3–4 cm pieces.

In a bowl, mash the tofu until smooth using a whisk. Add the seasonings (sugar, salt, soy sauce, and ground sesame seeds) and mix well.