Heat the broiler. Place the pineapple slices on a foil-lined baking sheet.
In a small bowl, combine the hoisin sauce, ginger, garlic and mustard. Rub pork w/ sauce.
Place pork in the broiler, about 4 inches from the heat; place the pineapple in the oven. Broil the pork until it registers 155°F on an instant-read thermometer, 15 to 20 minutes. Remove from the broiler (let rest 10 minutes before slicing- the temp. will rise to 160°F. as the pork sits). Turn the pineapple slices; cook until browned in spots, about 10 minutes more.
Halve pineapple slices; arrange on a platter with the sliced pork. Drizzle the pork with the pan juices; season with salt and pepper. Serve with quick ginger sauce.
To prepare sauce: In a small bowl, stir together all sauce ingredients; season with salt and pepper.
*Peeling ginger: I find that it's easiest to grate ginger when it's frozen. Cut the peel off and place it in the freezer for about 15 minutes or so before grating. When you're finished, you can put the remaining fresh ginger piece in a zip bag and keep in the freezer for future use. It keeps just fine in the freezer.
*Try grilling this recipe if you'd like. Grilled pineapple is fabulous!