Preheat the grill on high.

Place 1 piece of bread on a baking tray and grill on 1 side for 3 minutes or until toasted and crisp.

Repeat, in 3 more batches, with the remaining bread.

Meanwhile, cut each pineapple slice into 12 pieces.

Spread the untoasted side of each piece of bread evenly with pasta sauce.

Sprinkle the pizzas evenly with onion, ham, pineapple and mozzarella.

Lower the grill tray until the top of the pizza is about 12cm from the heat source.

Grill 1 pizza for 5 minutes or until light brown and heated through.

Transfer to a serving plate and cover with foil to keep warm.

Repeat, in 3 more batches, with the remaining pizzas.

Sprinkle the pizzas with parsley and cut into quarters to serve.