The broth base and filling. In a medium-large (4-quart) saucepan, heat the lard or oil over medium. Add the onions and cook, stirring regularly, until they are very well browned, about 10 minutes. While the onions are cooking, puree the undrained canned tomatoes (if using fresh tomatoes, puree them with 2/3 cup water), using a blender or food processor and working in two batches if necessary for your equipment.
When the onions are well browned, raise the heat to medium-high and add the pureed tomatoes, cinnamon and black pepper. Stir regularly as the mixture boils briskly, reducing until it becomes the consistency of thick tomato sauce, about 25 minutes.
The tomato broth. Remove 2 cups of the tomato mixture and set aside. Stir the broth into the mixture that remains. Partially cover and simmer over low heat for 45 minutes or so, while you’re preparing the filling and chiles.
The pork picadillo filling. Set a large (12-inch) skillet (preferably non-stick) over medium high heat. Add the almonds and stir around until they color to a deep golden, about 2 minutes. Remove. Crumble the pork into the skillet and fry, stirring often, until thoroughly cooked (some of the edges should be browned and crispy), 10 to 15 minutes. If the pork has rendered a lot of fat, drain it off. Mix in the reserved 2 cups of tomato mixture, raisins and vinegar. Cook over medium heat, stirring regularly, until the mixture is very thick and homogenous, about 20 minutes. Stir in the almonds, then taste and season with salt, usually about 1 teaspoon. Cool.
Preparing the chiles. While the picadillo is cooking, pour 1-inch of oil into a heavy deep skillet or pot—the pot should be 12 inches wide and 3 to 4 inches deep for easiest maneuvering of the chiles—and set over medium to medium high to heat to 360 degrees. (Using a thermometer is the most accurate way to assure the proper heat, but there are other reliable clues: The oil releases that “hot oil” aroma and its surface begins shimmering. When you think the oil is hot, test the edge of a chile—it should sizzle vigorously. Remember—smoking oil is dangerously overheated and will give the chiles a bad taste.) In two batches, fry the chiles, turning them continually for about 1 minute, until they are evenly blistered (they’ll look uniformly light green, having lightened as they blister). Drain on paper towels. Remove the oil from the heat.
When the chiles are cool enough to handle, rub off the blistered skins, then cut an incision in the side of each one, starting ½ inch below the stem end and continuing to within ½ inch of the tip. One by one, work your finger inside the chiles and dislodge all the seeds clustered just below the stem. Quickly rinse the seeds from inside the chiles, being careful not to rip or tear the opening any wider; rinse off any stray bits of skin. Drain on paper towels, cut-side down.
Stuffing the chiles. Stuff each well drained chile with about ½ cup of cool pork filling, then slightly overlap the two sides of the incision and pin them back together with a skewer or 2 toothpicks. For the greatest ease in battering and frying, flatten the chiles slightly, place on a parchment-lined baking sheet and freeze for about 1 hour to firm. (For notes on working with thoroughly frozen chiles, please read the note in Working Ahead )
Battering and frying the chiles. Reheat the oil to 360º and set up a tray lined with several layers of paper towels. Separate the eggs: whites into the bowl of an electric mixer, the yolks into another bowl. Add ½ teaspoon of salt to the whites and begin beating them on medium speed. When they are beginning to look dry and hold a stiff peak (but are not at all rigid), beat in the yolks two at a time until well incorporated. Lastly, beat in the 2 tablespoons of flour. Spread the 1 cup of flour on a plate.
One at a time, batter the first four chiles: roll in the flour, shake off the excess, pick up by the stem, dip into the batter, pull quickly straight up out of the batter, then lay into the hot oil. (If your kitchen is very warm, it’s best to hold the remaining batter for the second round in the refrigerator.) Once the first four are in the oil, begin gently, gently basting them with spoonfuls of hot oil (this will help set the uncooked batter on top). When they’re richly golden underneath, about 4 minutes, use one small metal spatula underneath and another one (or a spoon) on top to gently turn the chiles over. Fry until the other side is richly golden, another 3 to 4 minutes. Using the metal spatula, remove the chiles to drain on paper towels. Repeat with the second half of the chiles.
Serving the chiles. Heat the oven to 400º. Once all the fried chiles have cooled for at least 5 minutes, pick them up by carefully rolling each one onto one hand, then transferring to a baking sheet (lined with parchment, if you wish, for extra ease at the time of serving). Pull out the wooden skewer by twisting it gently. Bake for about 15 minutes to reheat, to render some of the absorbed oil and to crisp slightly.
Meanwhile, bring the tomato broth to a boil and check the consistency: it should be similar to a brothy tomato soup. If too thick, thin with a little water or broth; if too thin, boil rapidly until thickened slightly. Season it with salt, usually about ½ teaspoon. Ladle about ½ cup of the broth into each of 8 deep serving bowls (large soup bowls or pasta bowls are perfect here). Nestle in one of the chiles, garnish with the herb sprigs and get ready for a taste of real Mexico.
Working Ahead: The beauty of this dish is the way so many steps can be done in advance. The brothy sauce and filling (Steps 1 through 3) can be made several days in advance and stored in the refrigerator, covered. The chiles may be blistered, peeled and seeded (Step 4) a day in advance, though if I were that far ahead, I’d stuff (Step 5) and freeze them, too, just for ease in the frying. Battered and fried chiles will hold for an hour or two at room temperature before reheating them in the 400º oven (Step 7). (If you freeze the chiles until solid, be sure to complete the frying a full half hour in advance of oven-reheating and serving.) While reheating the chiles, warm the broth and you’re ready to serve.