Heat a very large straight-sided sauté pan with olive oil until smoking hot. Season the pork with salt and black pepper. Add the meat and sear well about 5 minutes. Add the onion and sauté about 2 minutes. Add the garlic and quickly sauté about 1 minute. Add the chicken stock, ancho chile powder, cinnamon sticks, chipotle pepper, zest of orange, orange oil, and dried oregano. Bring to a boil. Cover with a lid and place in the oven. Braise until tender about 40-50 minutes. Remove from the oven and skim the fat off the top. Season with salt and pepper. Serve warm with rice or soft polenta.