In a large skillet, heat 2 Tbsp olive oil over med. to med-high heat. Add chopped onion and saute until translucent and caramelized (about 5 minutes)
Remove onion from skillet or push to the side. Turn the burner up to medium-high for a sear. Sprinkle salt over both sides of the pork chops (add any additional spice or rub you like at this time).
Sear chops until well browned on one side and then turn to sear other side. Turn down the heat to med-low, cover the skillet and cook the chops for about 5-10 minutes or until no longer pink when you cut into it.
Remove pork chops from skillet and add tomato vinegar. It should sizzle when you add it, as you are deglazing the pan to get all the pork bits into the sauce. Cook down (reduce) over low heat until the tomato vinegar begins to get a little syrupy.
When the tomato-onion mixture is reduced, add 2 Tbsp butter and stir in until melted.
To serve. Spoon a little tomato-onion sauce on bottom of each plate, place the pork chop on top of the sauce and then drizzle more sauce over the top. Serve with sauteed spinach and a glass of dry red wine!