Slice the onion thinly. Trim the root of the shimeji mushrooms and separate them into bite-sized pieces.

Cut the thinly sliced pork belly into 3cm wide pieces and season with salt and pepper.

In a bowl, mix the sake, mirin, sugar, and miso to prepare the seasoning.

Heat salad oil in a frying pan over medium heat and cook the pork until its color changes.

Add the onion and shimeji mushrooms to the pan and stir-fry until softened. Add the prepared seasoning and stir to coat evenly. Add the pizza cheese and stir quickly.