Stale tortillas are best for this recipe, in any case when you have cut the tortillas intp strips spread them on a wire rack and leave for a couple of hours Combine pork, 1 onion& salt in a saucepan, cover with water, bring to a boil and turn the heat down, continue simmering, covered for about 1 1/2 hours or until the meat is very tender Pour the veggie oil into a pan and heat it to 375F and fry the tortilla strips until crisp-you may have to add a little oil but wait until it is hot before continuing, place the fried strips on paper towels to drain Heat 2 tbsp oil in a skillet and add the remaining onion, saute until soft 4 minutes Add the chilies, garlic& cumin, saute 1 minute.
Stir in the undrained, chopped tomatillos, bring to a boil and simmer covered 15 minutes Add creamo, cook uncovered over medium heat stirring frequently until the mixture has reduced to 2 2/3 cups about 12 minutes, stir in the cilantro Heat oven to 375 degrees F.
Mix cheeses in a small bowl.
Shred the pork (use 2 forks).
Spread half of the tortilla strips on the bottom of a shallow 2 1/2 quart, greased baking dish, add layer of pork, cream mixture and cheese, in that order and then repeat the layers Bake until hot through and golden on top appx 30 minutes.
Garnish with tomatoe slices and sour cream.