This is a slightly tweaked Rachael Ray recipe. I'm planning on trying it with raspberry balsamic vinegar. I also plan on spraying the plums with non-stick spray and grilling them on a regular gas grill, since I don't have a grill pan.
Preheat a grill pan to high heat. Drizzle fruit with oil to keep it from sticking and grill plums 3 minutes on each side.
While fruit is grilling, pour balsamic vinegar into a small pot and place pot over medium high heat. When vinegar heats to a boil, reduce vinegar by half, 1 to 2 minutes.
Combine sugar, vanilla and lemon juice and pepper in a small bowl. Whisk in warm balsamic vinegar.
Place hot, grilled fruit on dessert plates. Top with a scoop of ice cream, if desired. Drizzle with balsamic glaze and serve.