In large sauté pan or saucepan, heat lard or vegetable oil over high heat until very hot but not quite smoking.
Sauté the pork until golden on all sides, regulating heat so as not to burn.
Add garlic when meat is just partly browned (it burns easily if added earlier).
Add chile sauce and optional potatoes, bring to a boil, and simmer covered over medium heat until meat is tender but not overcooked, about 25 minutes.