Add butter to a pan and bring to medium heat. Fry mushrooms and onions, stir frequently.
Take another bowl and add eggs in that and whisk, add salt and pepper too.
Lower the heat and pour the eggs mixture over the mushrooms. Cook the eggs for 3-4 mins.
Crumble the cheese on the top, and cook the same for a minute more. Remove the sides with the help of spatula. Slide it on a plate and garnish with fresh parsley.