Open a can of sardines and separate sardines from the tomato sauce. Set aside the tomato sauce.
In a bowl put in eggs, a pinch of salt, a dash of ground pepper, maggi seasoning granules, red onion and sardines.
Mash the sardines and mix until texture softens.
Heat pan and drizzle with cooking oil.
Scoop a portion of the mixture then fry in medium heat until the bottom becomes firm. Flip the omelet to cook the other side. Side note, you can pour all the mixture once and spread it over the pan to minimize the time for cooking or follow our given procedure.
Repeat step 5 for the rest of the mixture, in case you're cooking the mixture in portions.
Once done frying all of the mixture, transfer on a plate. Another side note, garnish the tomato sauce over the sardines omelet or serve it separately.