Place tomatoes, onion, basil and balsamic glaze in a medium bowl and toss to combine. Season with salt and pepper.

Heat a lightly greased BBQ plate on medium-high. Combine butter and garlic in a small jug. Brush on to mushrooms.

Place the mushrooms stem side down on the barbecue for 3-4 minutes, or until charred.

Turn mushrooms. Top with torn bocconcini, close the lid, cook for 2-3 minutes or until the cheese is melted and the mushroom is warmed through. Transfer to a serving plate and top with tomato salad.