Wash the onion and mushrooms thoroughly and cut them into bite-sized pieces.
Heat cooking oil in a pan and sauté the onions.
When the onions become translucent, add the mushrooms and continue to sauté.
Add the rice and stir-fry everything together.
Season with soy sauce, salt, and pepper.
Once everything is well mixed and cooked through, turn off the heat and the dish is ready.