Step 1
To make the tomato chutney, use a small sharp knife to score a cross in the skin at the top of each tomato. Place tomatoes in a saucepan of boiling water and cook for 30 secs. Use a slotted spoon to transfer tomatoes to a bowl of iced water to refresh. Peel. Cut the tomatoes in half. Remove and discard the seeds. Coarsely chop the flesh. Heat the oil in a large saucepan over medium-high heat. Add the onion and mustard seeds and cook for 30 secs or until the mustard seeds start to pop. Add the curry powder, capsicum and apple and cook, stirring, for 3 mins until aromatic. Add the tomato, sugar, vinegar and salt and bring to the boil. Reduce to a simmer. Cover and cook, stirring often, for 45 mins or until the mixture thickens and the tomato is tender. Set aside to cool completely.
Step 2
Meanwhile, to make the aioli, use an electric mixer to whisk the egg yolk, mustard and vinegar in a medium bowl until pale and creamy. Add the garlic and whisk until well combined. Slowly add the oil to the egg yolk mixture, in batches, whisking constantly until the oil is incorporated and the mayonnaise is thick and creamy. Add a little water to loosen, if necessary. Season.
Step 3
Heat a barbecue grill or chargrill on medium-high. Season the steaks and spray with olive oil spray. Cook on the grill for 2 mins each side or until cooked to your liking. Transfer to a plate and set aside for 5 mins to rest. Cut in half. Drizzle with oil.
Step 4
Preheat grill on high. Cook rolls under the grill for 1-2 mins or until toasted. Top roll bases with cheese and cook under the grill for 2 mins or until just melted. Top the cheese with tomato chutney, steak, rocket and aioli. Top with roll tops to serve.