4-5 fresh serrano chiles, stemmed (you can use other fresh chiles as well)
3 garlic cloves, peeled
- Turn the oven down to 425 degrees. Separate the onion into rings and, on a similar pan or baking sheet, combine them with the garlic. Place in the oven. Stir carefully every couple of minutes, until the onions are beautifully browned. (They're going to look wilted and translucent, even have a touch of char on some of the edges.) The garlic should feel soft and be browned in spots. The total roasting time will be about 15 minutes. Cool to room temperature.
- In a food processor, place the onion-garlic mixture and the serranos, and pulse until moderately finely chopped, scraping everything down with a spatula as needed to keep it all moving. Scoop the mixture into a large bowl. Without washing the processor, coarsely puree the tomatillos with their juice--no need to peel off their darkened skin or cut out their cores. Stir them into the chiles. Stir in enough water to give the salsa an easily spoonable consistency. Stir in the cilantro.
- Taste and season highly with salt. Taste again and, if you like, add just enough sugar to take the edge off the bright tanginess of the tomatillos. The salsa is ready to use or store in the fridge, covered, and use within 5 days.