Add miso, sugar, mirin, sake and garlic in a mixing bowl. Mix well.
Marinate the pork chop with miso sauce for at least 1 hour in the fridge.
Prepare truffle rice: Add 1 tbsp of olive oil to a large flat-bottomed cast iron pan and heat over medium heat. Add garlic and saute for a few minutes.
Add in the brown, shitake and shijimei mushrooms. Saute until fragrant.
Add in the rice and stir well.
Add in the soyu sauce and mix well.
Pour in the mushroom broth, simmer for a few minutes and transfer all to a rice cooker and let it cook.
In a heated pan add oil. Add the pork chop in and fry until both sides are golden brown.
Glaze pork chop with the remaining marinade and place in the oven for 20mins at 180°C. Once the pork chop is out from the oven, you may torch the pork chop until slightly charred.
Let the pork chop rest for at least 10mins before cutting into thin slices.
Add truffle oil to the cooked mushroom rice and stir well.
Scoop the mushroom rice to a bento box and placed sliced pork chop nicely on top. Garnish with spring onion and onsen egg.