This tofu recipe is inspired by chawanmushi, a Japanese custard that is very soft and delicate, made with lots of liquid, which flows out of the custard as you eat it. Incorporating soft tofu with the eggs makes the custard firmer and more substantial. Besides shrimp, this custard could be made with scallops, cooked lobster, crab or cooked fish. Serve as a first course or for lunch with a side of vegetables and rice.