Season both sides of the pork chops with kosher salt and freshly ground black pepper. Set aside while you prepare the pasilla sauce.
Heat up a comal or griddle over medium heat and slightly toast cleaned pasilla peppers until fragrant and just beginning to change color.
Place peppers in a medium bowl and cover with boiling water; set aside.
Remove husks from the tomatillos and place in a large sauce pan. Add garlic cloves and ½ of the onion. Add water until just barely covering the tomatillos. Bring to a boil and continue to cook for 10 – 12 minutes until you see the tomatillo change in color. They should be soft, almost translucent, but not falling apart. Using a slotted spoon, remove the tomatillos, garlic and onion and place into a blender.
Drain the pasilla peppers. Add drained peppers to the blender with the tomatillos. Blend all ingredients until smooth. Strain and set aside.
Heat a large frying pan over high heat. Add 2 tablespoons Wesson oil. Add seasoned pork chops and let cook for 3 minutes until golden brown, flip and continue to cook an additional 3 minutes. Remove pork chops from pan and set aside. Reduce heat to medium low and add the remaining ½ onion. Add prepared pasilla sauce and piloncillo. Taste for seasonings and if needed, add salt, pepper.
Cover and simmer for 20 - 30 minutes until chops are tender. Remove from heat and let stand 10 minutes before serving.