Throw in the onions, water to cover the meat, chile powder, cumin, Mexican oregano, garlic and tomato sauce. Season to taste with salt and pepper. Stir the pot until well-incorporated. Bring the liquids to a boil, cover, cut the heat to a slow simmer and cook for 1 1/2 hours. Stir the pot - on occasion.
If necessary, thicken the liquids with a slurry of Masa Harina, dissolved in water at 1 part Masa to 1 part water.