Wash the strawberries, cut off the greens, then marinate in a bowl with sugar, Grand Marnier and aceto. Place the strawberries in an ovenproof bowl with the tip up, sprinkle the flakes with butter. Place the pan on the grill and grill for 7-8 minutes with the grill lid closed (if present). If you don`t have a lid, cover the baking dish well with aluminum foil.
Serve the hot strawberries with a scoop of vanilla ice cream