1. Heat a grill pan on the stove or a grill press. Slice apple into thin rounds and place on grill until just soft, 2 to 3 min.
2. Cut bread into 4 pieces; slice pieces or rolls in half lengthwise. Divide Brie among sandwiches. Top with salami, apples and remaining bread.
3. Brush sandwiches with olive oil and grill until cheese is melted and bread is just crisp, about 7 min; serve hot. Makes 4 paninis.