Egg hoppers are more identified with Srilanka than Kerala, I think. Even in Kochi, it is not common in a restaurant menu that reads out a mutta velleppam / appam. Recently, i saw the TV series - My Srilanka with Peter Kuruvita. The batter prepared for appam is slightly different from mine. In the TV series bread is used instead of yeast. Mine has even more difference. I don't use the coconut milk version. I follow the recipe where coconut is ground along with rice. This is much easier because there is no task of extracting the coconut milk and then cleaning up many vessels. The secret of my recipe is the addition of coconut water. Egg hoppers have crispier edges than usual hoppers because the egg is poured into the cooked palappam otherwise the middle of the appam will remain undercooked or even uncooked and messy.
The rule of thumb therefore is to break the eggs in when the appam is almost cooked. Sprinkling salt and pepper is optional, but i prefer it, as it gives more taste.
recipe for egg hoppers or mutta appam
appam batter (click here for recipe) - as much as you need
eggs - 1 per appam / hopper
Heat a deep pan, as seen in the first picture. Grease it with oil cloth or just use back of a spoon to spread 1 or 2 drops of oil. Pour a ladleful of appam batter. Swirl the pan to let the batter coat the pan. For egg hoppers make sure there is not much batter to collect in the middle. Put the lid on and cook in medium heat. This ensures that the sides are still soft. Once the middle the appam has lost its whitish colour or has turned pale, break an egg in. Sprinkle some salt and pepper ( i rubbed together a tiny pinch of salt and a tiny pinch of pepper in advance, so that it is evenly spread on the egg). Cover and let the egg cook in low heat. Low heat is required to cook this step, so that the sides do not turn dark brown. Remove the egg hoppers from the pan when the eggwhite is completely cooked and the egg yolk is slightly gooey. It will cook itself by the time it is served. Serve with a bean curry, like garbanzo bean curry / kadala curry (masala curry) or green peas green kurma or a vegetable kurma.