16serrano chiles, roasted, peeled, seeded, and diced
¼cup freshly squeezed lime juice
1cup chopped cilantro
In small saucepan, combine the vinegar, sugar, and allspice and simmer until the sugar dissolves. Set aside.
Heat the oil in a medium-size skillet over medium heat; stir in the onion and cook until translucent, about 4 minutes. Add the serranos, allspice-vinegar syrup, and salt and gently simmer until the mixture binds together, 8 to 10 minutes.
Cool, fold in the lime juice and cilantro, scrape into a food processor, and process until blended but still slightly chunky. Taste to adjust the salt, if needed.