Takikomi Gohan (Japanese Savory Mixed Rice)

Put water in a pot and bring it to a boil. Once boiling, reduce the heat to low, add bonito flakes, and let it simmer for 3 minutes.
Turn off the heat and strain the mixture through a sieve lined with paper towels or a cloth (such as cheesecloth). Alternatively, if you don't mind having some fine bonito flakes remaining, you can simply use a fine-mesh strainer. Bonito dashi is now ready.
Place a sieve over a bowl, add rice, and rinse it with water. Repeat this process several times, changing the water each time.
Soak the rinsed rice in the dashi (⅚ cup/200 ml per 2 servings) in a pot for at least 30 minutes.
Place aburaage in a heatproof bowl and pour boiling water over it to remove excess oil. Remove it from the bowl, and once it has cooled enough to handle, drain off the water.
Cut aburaage, pork belly, and carrots into small, bite-sized pieces. Trim off the base of shimeji mushrooms and separate them into individual pieces.
Sauté the pork in a pan over medium heat and sprinkle it with salt.
Combine seasonings (mirin, salt, and soy sauce) with the rice in the pot. Then, evenly distribute the aburaage, pork belly (including pork fat from the pan), carrots, and shimeji mushrooms on top.
Cover the pot and bring it to a boil. Once boiling, reduce the heat to low and continue cooking for 10 minutes, or slightly longer for larger quantities (11 minutes for 4 servings, 12 minutes for 6 servings).
Turn off the heat and let it steam for 10 minutes with the lid still on.