Put 5 green plantains in hot water for 2 minutes. Make lengthwise cuts extending into the skins on a side and along the ridges. Peel off left over skin. Cut each plantain to half the length and split each into half along the long side. Boil them until soft (15 minutes). Fry onions bashed with vinegar. Fry salami and cheese. Put the soft plantains in a large bowl. Add in 3 tbsp butter. Mash the plantains. Add 3 tsp water. Derve the plantain with onion.