How to Make It
Place beans in a large pot; add water to cover by at least 2 inches. Let soak at least 8 hours or up to overnight. Drain beans.
Combine drained beans, 5 cups water, onion, garlic, and avocado leaves in a large pot; bring to a boil over medium. Cover and reduce heat to medium-low; simmer, stirring occasionally, until beans are tender and creamy, 1 hour and 30 minutes to 2 hours. Remove from heat. Remove and discard onion, garlic, and avocado leaves. Stir in epazote and salt. Drain beans, reserving cooking broth.
Combine chile, 2 cups cooked beans, and 2 1/2 cups bean cooking broth in a blender. (Reserve remaining 4 cups beans and any remaining cooking broth for another use.) Process mixture until smooth, about 30 seconds. Set aside.
Heat 1/2 cup oil in a large skillet over medium. Fry tortillas, 1 at a time, until soft and pliable, 10 to 20 seconds per side; transfer to a baking sheet lined with paper towels to drain. Set aside.
Heat remaining 1 tablespoon oil in a medium saucepan over medium. Add bean mixture; cook, stirring often, until simmering, 4 to 5 minutes. (The consistency should be similar to heavy cream; stir in water or additional reserved cooking broth, 1/4 cup at a time, if needed to loosen.) Remove from heat; season with salt to taste.
Place 1 tortilla in hot bean mixture in pan; let soften, about 15 seconds per side. Place tortilla on a serving plate, and fold in half. Repeat process with remaining 11 tortillas, placing 3 folded tortillas on each of 4 plates.
Spoon remaining hot bean mixture evenly over tortillas (about 1/3 cup each). Sprinkle evenly with Oaxaca cheese and queso fresco; garnish with sliced onion and chopped parsley.
Lightly malty Mexican lager: Modelo Especial. (Turn the Modelo into a michelada using Guelaguetza I Love Micheladas mix.)