In a bowl break two eggs, little salt and mix it well and keep it aside. Now heat the pan at medium heat and add oil.
Now add onions, bell pepper and salt. Mix well and let it cook till onions are little soft.
Once onions turn little soft add mushrooms, saute and cook till mushrooms are roasted and dry.
Once veggies are soft and dry put the egg on it and spread it all over the pan. Once egg is half cooked scramble it and cook till it’s almost done.
Now switch off the heat and put cheese slices on egg and cover it and let it melt. In the meanwhile mix mayonnaise and ketchup in a bowl and also toast the breads.
Apply thin layer of mayo-ketchup mixture on one side of toasted breads. Now stuff the cheese omelette between these breads. Cut it in half and serve it hot.