From Simply Recipes, which has a beautiful picture and a great story and more. I’m just writing it here so I don’t wonder, next year, what recipe I used.
1 lb serrano or jalapeño chile peppers
1/3 cup olive oil
2 medium white onions, thickly sliced
2 medium carrots, peeled and thickly sliced
1 head garlic, cloves separated but not peeled
3 cups apple cider vinegar
2 Tbsp Kosher salt or sea salt
2 bay leaves
1/2 teaspoon dried oregano
4 sprigs of fresh marjoram or 1/4 teaspoon dried
4 sprigs of fresh thyme or 1/4 teaspoon dried
1 Tbsp sugar
1 Wash the chiles, leaving the stems intact. Cut a cross in the tip end of each chile so that the vinegar will be able to penetrate.
2 Heat oil in a large, deep skillet. Add the chiles, onions, carrots, and garlic. Fry over medium heat for about 10 minutes, turning them over occasionally.
3 Add the vinegar, salt, herbs, and sugar and bring to a boil. Lower the heat and simmer for 5 minutes for serranos or 10 minutes for jalapeños.
4 Pack 6 half-pint sterilized jars with the chiles and vegetables. Top with the vinegar and seal. Process in a hot water bath for 10 minutes.
Once opened, can keep for one month in the refrigerator.
Note from Diana Kennedy is that partially cooked chiles allow for the growth of bacteria. It is very important to cook the chiles thoroughly if they are to be stored for any length of time.
Recipe adapted from The Essential Cuisines of Mexico.