Preheat oven to 200 deg C.
Place the egg whites in a large bowl. With a handheld blender, whip the egg whites till they are stiff.
Add the onions, tomatoes, green chilies, coriander leaves, and salt to taste to the whipped egg whites. Fold very gently with a flat spatula in one direction.
Cut out small squares from the buns leaving the margins intact. Remove any bread visible inside the cavity made.
Ladle the white foamy whipped egg whites inside the cavity. Make sure it's filled out right till the top. sprinkle some shredded cheese.
Now make an indentation in the center of the egg whites and place the egg yolk in it. Sprinkle little salt and shredded cheese over the egg yolks.
Bake in the oven for 10 minutes or until the yolks are set. If runny yolk is desired, bake for less time.
Serve immediately with hot coffee on the side.
