Dominican mangú with fried onions

Directions

1. Peel the green plantains using a knife. ≈ 8 min
2. Cut each plantain in half, then cut each half into four pieces. ≈ 8 min
3. Boil water with 2 teaspoons of salt, then add the plantain pieces. ⏱ ≈ 10 min
4. Continue cooking until the pieces are tender and easily pierced with a knife, then remove from the heat and drain. ⏱ ≈ 10 min
5. Mash the plantains with a fork to create a puree. ≈ 4 min
6. Immediately add the butter, so that it melts and mixes with the puree. ≈ 3 min
7. Add the cold water gradually until you achieve a smooth, creamy consistency; otherwise, use milk. ≈ 4 min
8. Finely chop the onion, into thin slices. ≈ 8 min
9. Heat the oil in a frying pan. ⏱ ≈ 7 min
10. Sauté the onions until they become translucent, then add the vinegar and salt to taste. ⏱ ≈ 7 min
11. Arrange the onions on top of the mashed potatoes and serve. ≈ 2 min