Add the vinegar, sugar, and vanilla to a saucepan set over medium heat. Bring to a boil, then simmer until reduced by about half and thick enough to coat the back of a spoon (about 10 minutes). Remove from heat and stir in the black pepper.
Lightly coat the lamb chops with olive oil. Sprinkle with rosemary and sea salt. Place in a single layer on a broiling pan. Broil under high heat for 5 minutes on each side.
Brush the lamb chops with the vanilla balsamic glaze. Serve with remaining glaze. Sprinkle with pomegranate seeds, if desired.