Peel the Plantain (4) and cut into 4 pieces. I like to cut length in half and slice in half, making it 4 pieces.
Boil the plantains in water with Salt (1 teaspoon) until they are very tender.
When tender mash them with a fork until they are smooth. Add cooking water as needed to keep the plantains moist. Once smooth, add Corn Oil (2 tablespoon) and mix further.
You can make the onions in 2 ways. You can heat Corn Oil (1/4 cup) in a skillet. Add Red Onion (1) stir until they become translucent or reach desired tenderness. Add White Wine Vinegar (1 tablespoon), stir well and you are done!
You can also place all the ingredients in a small bowl and heat in microwave 3 minutes or until desired tenderness. I suggest you stir a bit every minute.
Slice the Queso de Freir (1 package). Add flour to a paper plate and lightly cover each slice of cheese. In a skillet, add Corn Oil (to taste) and fry over medium heat until golden. Keep warm in the oven.
Slice the Salchichón (1 pound). In a clean skillet, add Corn Oil (to taste) and fry the slices over medium heat until golden. Keep warm in the oven.
In a clean skillet, add a generous splash of Corn Oil (to taste), fry the Egg (4) one at a time. (Do this right before you plan to eat).
Serve the mangú, place cheese, salami and eggs around the mangu and pour desired amount of onion garnish over the dish.