Peel and deseed rockmelon. Using a V-slicer or sharp knife, very thinly slice rockmelon. Toss rockmelon with lemon juice and chilli flakes in a bowl. Set aside.

Heat oil in a large frying pan over medium-high heat. Add haloumi and cook, turning once, for 1 to 2 minutes until hot and golden. Drain on paper towel.

Arrange rockmelon on a serving platter. Top with haloumi and sprinkle with red onion, mint and pistachios. Season with black pepper, drizzle with extra virgin olive oil and serve.