Cut the end of the plantains and cut them in half.

Cut a shallow slit down the length of each ridge, but don't cut too deep, just the skin.

Use your fingers to remove the skin from the flesh.

Cut the peeled plantain into smaller pieces, like 4 to 5.

Add the plantain pieces to a pot and add water and salt. Bring it to a boil and cook for 20 minutes or until tender.

Peel the onions and cut them into rings.

Use a pan and saute the onions in olive oil for about 2 minutes on medium-high heat.

Add 100 ml water, cover, and let it cook for 5 minutes.

Add salt and vinegar and cook for another 2 minutes.

Remove from the stove and set aside.

Remove the plantains from the water and mash them with a potato masher or fork. Add ice cold water and butter and mash until smooth.

Add salt and olive oil. Use a hand mixer for extra smoothness, if available.

Serve the mashed plantain on a plate, garnish with the sauteed onion and vinegar juice.