Make the marinade: Finely chop the oregano, rosemary, thyme, epazote and garlic. Mix together with 1 tablespoons salt. Stir in the olive oil until the mixture is spreadable. Cut the ribs in half if they don't lie flat in the pot. Rub the marinade thoroughly into the meat and cover with plastic wrap. Place in the refrigerator. The lamb needs to marinade overnight, or for at least 8 hours.
When ready to cook, start by softening the guajillo chiles in boiling water. Remove the vein and divide into large pieces. Soften the maguay or platano leaves by placing them over an open flame and roasting until they are tender and pliable. You will likely need to cut the leaf into 4 to 8 pieces depending on the size. The pieces should be long enough to envelope the meat while cooking, yet thin enough to be pliable.
In a large stainless steel steamer pot with 2 inches of water in the bottom, place about 4 pieces of the maguay on the bottom so that it creates a layer on the bottom while the ends stick up out of the pot. Place a layer of meat, then a layer of guajillo chiles (1 to 1 1/2 per layer depending on size), then a layer of avocado leaves. Place another layer of meat, followed by the chiles, then the avocado leaves. Repeat one last time. Fold the maguay around the meat. Place the remaining maguay leaf pieces on top of the meat and cover with plastic wrap. Over a low heat, bring the water to the steaming point and maintain a constant steam for 2 to 2 1/2 hours.
To serve, remove the meat from the bones, place in a tortilla and add cilantro and onions, plus a strip of jalapeno and salsa to taste. Any remaining cooking liquid can be put in a bowl or cup and sipped, or used to dip the tortillas in.
Have your butcher cut the lamb into 4 pieces.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.