(Adapted from Mayan Cuisine: Recipes from the Yucatán Region)
2 large red onions, peeled
1 cup apple cider vinegar
1/2 cup sour (Seville) orange juice*
1 clove garlic
1 teaspoon whole allspice berries
2 teaspoons black peppercorns
4 bay leaves
2 sprigs fresh marjoram, thyme or oregano
1 whole habañero chile
2 tablespoons brown (or raw) sugar
1/4 teaspoon salt
Slice the onions into thin rings and place them in a large, glass bowl (of a sufficient size to comfortably hold the pickling juice).
Mix together the remaining ingredients in a nonreactive saucepan. Bring to a boil and cook 5 minutes.
Pour the hot mixture through a strainer over the onions; stir with a wooden spoon. Leave the bowl on the counter, stirring occasionally, until the onions soften and are completely submerged. When cool, pour into a jar and refrigerate if not serving immediately.
* Goya sour orange juice can be found in the grocery store aisle where Latin American foods are found. As a substitute, Diana Kennedy (the Julia Child of Mexican cooking) suggests blending 1 teaspoon finely grated fresh grapefruit rind, 3 tablespoons orange juice, 3 tablepoons grapefruit juice and 2 tablespoons lemon juice.