Preheat oven to 400. Spray roasting pan with nonstick spray
Stir together garlic, rosemary, salt, and pepper in small bowl, Rub mixture over pork. Place pork in roasting pan and roast 30 minutes.
Stir together jam and mustard (or balsamic vinegar) in small bowl and brush all over pork. Continue to roast pork until an instant read thermometer inserted in center registers 145 degrees, about 5 minutes longer. Transfer to cutting board and let stand 10 minutes. Cut roast into 12 slices.