1. Heat 1 tablespoon oil in a large skillet over medium-high heat. Sprinkle the pork chops with salt and pepper and add to the hot oil. Cook, turning once, until nicely browned and still a little pink inside, about 7 minutes. Transfer to a plate. Reduce the heat to medium.

2. Add the remaining tablespoon oil and the onion to the skillet. Sprinkle with salt and pepper, and cook, stirring, until crisp-tender, about 3 minutes.

3. Add the vinegar and cook, stirring and scraping the pan, until reduced to a syrup, about 1 minute. Add the pineapple with the juice and cook, stirring, until most of the juice evaporates, about 2 minutes. Spoon over the pork chops.