1Slice carrot into 1/4 inch slices (cut into flower shape if desired). Bring salted water to a boil, reduce heat and blanch carrots and prawns until prawns just start to turn opaque. Drain and set aside.
2Cut the chicken into small cubes and marinate in sake and soy sauce for 15 minutes.
3Whisk all custard ingredients together in a bowl and strain through a mesh strainer.
4Place a bamboo steamer basket over a pan of water and bring to a boil. Reduce heat to low.
5Divide the chicken, shiitake, prawns and carrots among four ramekins. Divide the egg mixture among the ramekins. Put the scallion on top and cover each ramekin with aluminum foil. Steam on low heat for 15 minutes. Insert a toothpick into the center of the egg and if it comes out clean, they are done.