Place your Sizzler Pan in your oven to preheat. Once heated, remove the Sizzler from the oven. Add the olive oil, then the onion and salt, and stir well to coat the onion. Place the Sizzler inside the oven for 10-15 minutes – stirring occasionally to prevent sticking – until the onions have sweated down and are translucent. Sprinkle over sugar and cook for a further 10 minutes in the oven until caramelised. Set aside.