-
Preheat oven to 400 degrees.
-
In a microwave safe large cup, heat the vinegar and brown sugar for two minutes until sugar is dissolved and mixture starts to thicken.
-
Put grapes in a 9 x 13” baking pan lined with aluminum foil and pour the vinegar mixture over the grapes, mixing well.
-
Roast the grapes for 1 hour. Lower the oven temperature to 250 degrees and bake 2 more hours. Raise the temperature to 450 degrees and bake the grapes for another half hour, watching carefully so they do not burn. Remove from oven and set aside.