Prepare the takikomi gohan mixed rice: Start by rinsing 450g rice in water by hand a few times until the water becomes clear. Set rice aside to soak. Slice up 1/2 of the gobo burdock root and soak it in water for 5 minutes along with 4 shiitake mushrooms. Now remove and discard the stems from the shiitake mushrooms and slice the remainder of the shiitake mushrooms, takenoko bamboo shoots, renkon lotus root and carrots into small thin pieces or strips.
Create the dashi stock: Add a sachet of dashi powder with 600ml water. Bring the dashi stock to the boil and then boil the shiitake mushrooms, burdock root, bamboo shoots, lotus root and carrots for 5 minutes. Drain the vegetables, and reserve the dashi stock for later.
Drain and add the rice to your rice cooker or pan: Place the vegetables on top of that. Pour in the reserved dashi stock plus extra water to make 600ml to make up for any liquid lost during boiling. Then cook as you would normally cook rice. Once the rice is cooked, mix and fluff the rice to ensure the vegetables are evenly distributed. Set aside.
Prepare tamagoyaki egg omelette: Heat 1 tsp of oil in a medium sized frying pan or tamagoyaki pan if available, and pour in the egg mixture a little bit at a time. Swirl the egg around in a thin layer and cook on medium heat until the bottom is cooked. Roll up the layer of egg, and push to the back of the pan. Then add some more of the egg mixture to make layers for the tamagoyaki omelette. Repeat making layers until the egg mixture is used up.
Prepare the simmered prawn and vegetables: Peel 1/4 carrot and chop into thin slices. You can use food cutters at this point to make the carrots into decorative slices. Next, bring the dashi stock (use about 1/5th of a sachet of dashi stock powder, and 120ml of water), soy sauce, mirin and cooking sake to the boil in small saucepan. Add the prawns, shiitake mushrooms and carrot slices to the pan and simmer over medium heat until the prawns are cooked through, about 3-4 mins. Strain and set aside. Cut the chestnuts in syrup into small bite size pieces. Set aside.
Arrange each dish in the bento box: Serve while enjoying the nice autumn scenery.
