Cook the beans. If cooking on the stovetop, measure the beans into a large (4-quart) saucepan. Add the optional avocado leaves, the chipotles, garlic and 6 cups water. Bring to a boil, partially cover, then reduce the heat so that the beans simmer very gently until tender, usually about 2 hours. If the water drops below the level of the beans, add more, so that they float freely.
If using a slow-cooker, combine the beans, avocado leaves (if using), chipotle chiles, garlic and 6 cups water and cook covered on high until the beans are completely tender, usually about 6 hours.
If using a pressure cooker (like an Instant Pot), combine the beans, avocado leaves (if using), chipotle chiles, garlic and 6 cups water and pressure cook for 1 hour, until the beans are tender. I let the pressure release naturally for 15 minutes, then release the pressure valve and continue with the recipe.
Make the sauce. Strain the beans over a bowl and pour all the broth into a blender jar. Remove the avocado leaves (if using), then measure ¾ cup of the beans in with the broth and blend until completely smooth. (Refrigerate the remaining beans for another dish—they are perfect for classic Mexican fried beans.) Pour the sauce into a medium (3-quart) saucepan, set over medium heat and simmer briskly, stirring occasionally, until the consistency is that of a cream soup (the quantity will have reduced to 2 ½ cups), about 30 minutes. Taste and season with salt, usually a generous teaspoon. Cover and keep warm on low heat.
The garnishes. In a medium (9-inch) skillet, fry the chorizo over medium heat, breaking up clumps, until browned and completely cooked through, about 10 minutes. (If the chorizo doesn’t immediately start to render fat, you’ll want to add a little oil to the skillet to ensure even cooking.) Use a slotted spoon to scoop the chorizo onto a plate lined with paper towel to drain. (And you can save the fat to fry the leftover beans in!). Set out the salsa, cheese, sliced onion and parsley because assembling the enfrijoladas goes quickly.
The tortillas. Lightly brush or spray both sides of each tortilla with oil. Slide into a plastic bag (don’t seal) or wrap in plastic and microwave at 100% power for 45 seconds to warm and soften. Let stand 1 minute until cool enough to handle.
Finish the enfrijoladas. Set out 4 warm dinner plates. One by one dip the tortillas into the hot bean broth, lay on a plate, then fold in half. Arrange 3 tortillas on each plate, slightly overlapping. Ladle a portion of the hot sauce over each serving, spoon on chorizo, splash on the salsa, sprinkle with the cheese and strew with parsley leaves. Serve without hesitation.