Once they are boiled, cool them down and remove the whites from the yolk
Then add the egg yolks in a bowl, Add 1/4 cup of finely chopped onions, 1/4 cup of finely chopped of tomatoes, 1/4 cup of finely chopped of cilantro leaves and 2 tbsp of mayonnaise.
Add the egg whites and required amounts of 1 tbsp of salt and pepper.
Mix it well
Take 2 slices of bread and heat it well in a pan and add some butter
Then place the slices in a plate and add the mix to both the bread slices