Making the Sauce
1.Turn the oven on to broil and place the tomatoes in an oven-proof casserole. Slide the casserole under the broiler and turn the tomatoes every few minutes until they are black in spots.
2.Remove the tomatoes from the oven and turn the oven down to 325 degrees F. Remove the stems and seeds from the chiles.
3.Peel and seed the tomatoes and put them along with 2/3 of the onion, the chiles and their sauce, garlic and salt in a food processor.
4.Heat the lard or oil in a small saucepan over medium-high heat. Puree the tomato mixture.
5.Add the tomato puree to the hot oil while constantly stirring. Cook and stir for 4 minutes.
6.The puree will turn a slightly darker color. Add the broth and keep warm.
Tips: Frying the puree is a little tricky and messy because it splatters. Watch the heat of the oil to prevent too much splattering.
Assembling the Dish
7.Heat the remaining oil in a small saute pan over high heat. Place the tortillas in one stack and cut them into eight wedges.
8.Fry the tortilla wedges using tongs, until they are just golden and slightly crispy. The tortillas should still be slightly flexible.
9.Drain the tortillas on a plate lined with paper towels to remove excess grease. Put a layer of sauce in the bottom of the casserole dish.
1..Add a single layer of tortilla wedges and then some of the chicken and cheese.
1..Repeat this process until all of the tortillas, sauce, chicken and cheese are used. Place the casserole in the oven and bake for 15 minutes.
1..Serve with a few onion slices and a little of the crema mexicana drizzled over the top.
Tips: You can use sour cream or heavy cream as a substitute for the crema mexicana.
Making the Sauce