Tortoiseshell Tofu

2 c. dashi
1/2 tbsp sugar
2 tbsp mirin
2 tbsp soy sauce
pinch salt
1 cake tofu, pressed (if not silken)
3 tbsp cornstarch in 3 tbsp water
kinome sprigs or finely shredded fresh ginger

Mix dashi, sugar, mirin, soy sauce in a medium pot, boil, simmer, add salt.
Cut the tofu into quarters, slide them into the pot (try not to break them). Ladle the liquid over the tofu until heated thoroughly, about 4 minutes. Remove tofu, keep on the heat, add the cornstarch/water. Stir until thickened, about 1 minute.
Ladle sauce over tofu, garnish, eat with spoons instead of chopsticks.

Source: Japanese Cooking, a Simple Art, by Shizuo Tsuji, p. 398-399