Place 6 main eggs in a saucepan and add enough water to cover them. Bring the water to a boil, then reduce the heat and let the eggs simmer for 10 minutes.
Remove the eggs from the saucepan and place them in a bowl of cold water for 5 minutes to cool down. Once cooled, peel the eggs and cut them in half lengthwise.
Carefully remove the yolks from the egg whites and place them in a separate bowl. Mash the yolks with a fork until smooth.
Add 3 tablespoons of mayonnaise, 1 teaspoon of mustard, a pinch of salt, and a pinch of black pepper to the mashed yolks. Mix well until the filling is creamy and smooth.
Use a spoon or a piping bag to fill the egg white halves with the yolk mixture. Garnish with a sprinkle of red chili powder or paprika and chopped coriander leaves.