To make the raspberry sauce, place the raspberries, sugar, and balsamic vinegar in a food processor and liquidize till smooth. Sieve to discard seeds and pour in jug.
Preheat the chargrill on high heat. When hot, place peach quarters on the grill. Leave for 1-2 minutes on each side, then carefully lift with an offset spatula and place on a tray to cool.
To serve, place peaches on serving dishes with a scoop of vanilla ice cream and a drizzle of raspberry sauce on top.