Boil the potatoes until tender. Peel them, keeping the skins.
Air fry the potato skins at 180°C for 4–5 minutes until slightly dried.
Shred the potato skins and mix with the grated cheese and sesame seeds.
Cut the boiled potatoes into bite-sized chunks.
Gently mix the potatoes with the tuna, Dijon mustard, mayonnaise, olives, broccoli and spring onions.
Place the frozen roti into an air fryer-safe baking dish and blind bake at 180°C for 15 minutes. Remove and let cool slightly.
Spoon the filling evenly over the roti base.
Scatter the potato skin crumble over the top.
Drizzle lightly with the oil.
Air fry at 180°C for 10-12 minutes, until the crumble is crisp and golden.
Rest for 5 minutes before serving.