Bring a large pot of salted water to the boil. Cook the pasta for 2 minutes less than the packet's al dente time, then drain immediately - it will finish cooking in the oven, which is what keeps the bake from drying out.
Heat the olive oil in a frying pan over medium heat. Add the chopped onion and cook for about 5 minutes until softened, then stir in the garlic and cook for a further minute.
Pour in the double cream and bring to a gentle simmer. Stir in most of the cheddar (reserving a handful for the topping), the oregano, basil, salt and pepper, until melted into a smooth, loose sauce.
In a large bowl, combine the underdone pasta, drained tuna, sweetcorn, and the sauce. Transfer to a baking dish and scatter over the reserved cheddar, the Parmesan, and breadcrumbs if using.
Air fryer: 180°C for 15-20 minutes. Oven: 200°C (180°C fan) for 20-25 minutes, until golden and bubbling on top.