"This was one of the most popular college potluck dishes among Taiwanese students studying at American universities back in the 70s. It's continued to be everyone's absolute favorite, and just couldn't be easier to make since it's just 1-2-3-4! Serve over white rice."
Place tomato wedges in the bottom of a large pot over medium heat. Lay pork ribs on top. Add vinegar, sugar, and soy sauce in that order. Bring to a boil. Stir and cover pot partially with a lid. Reduce heat and simmer, stirring occasionally, until pork is tender, 30 to 40 minutes.