Heat up a pot of water and add dashi stock. Once it comes to a boil and stock has fully dissolved. Turn off heat and set aside.
Heat up a pan and add oil. Sweat down the shallots until translucent.
Add sliced mushrooms. Try not to crowd the pan and give the mushrooms space and time to cook down. Add light soy sauce over mushrooms. Let sit undisturbed for 2 minutes and then give it a stir.
Add dry arborio rice. Toast the rice until the kernels start to become a golden brown.
Add white wine or sake to deglaze the pan.
Add ½ cup of dashi stock at a time. Continue to stir so the rice doesn't stick to the pan. When the liquid is almost completely absorbed, add another ½ cup of dashi stock.
Repeat the step of adding in dashi stock and stirring until rice is tender but still al dente. The final result should look like thin oatmeal. This should take around 5 cups of dashi stock to achieve.
Add in chopped scallions and white toasted sesame seeds and serve! Feel free to also add more salt and black pepper to taste, if needed!