Peel the Plantain (4) and cut lengthwise, then divide each half into two.
Add plantains to a large saucepan, add enough water to cover them ( I added five cups of water). Turn on the heat to high and bring to a boil.
Once it is at boiling point, add Salt (1 tablespoon), stir and reduce heat to medium high and boil for 18-20 minutes or until they are tender.
About 10 minutes before plantains are done, add frying Cooking Oil (2 tablespoon) to a skillet over medium-high heat. Fry the Egg (to taste) to your liking.
Then fry the Cheese (to taste) until it's golden brown on both sides. Fry the Dominican Salami (to taste) until it develops color on both sides.
To fry the onion, in a skillet over medium high heat, add Cooking Oil (1/2 cup) and let it get warm, add sliced Red Onion (1), Distilled White Vinegar (1 tablespoon) and Salt (1/4 teaspoon), stir and cook for 2 to 3 minutes until it softens a little.
Drain plantains leaving a little bit of the cooking water behind, mash them with a potato masher or a drinking cup, preferably plastic or aluminum. Once mashed mix in Butter (6 tablespoon) and continue mashing until smooth, some lumps are ok!
Add the Water (1/2 cup) and stir to incorporate, then add the oil from the onions and stir. Serve!