Halve and deseed the chilli, trim and halve the spring onions, then finely slice them both lengthways to create long thin strips. Place in a small bowl of iced water and leave to curl up while you cook your egg.
Place a small frying pan over a medium heat with the curry paste, and cook for 1 minute until fragrant. Finely chop the coriander stalks, reserving the leaves for later, then stir into the paste for 30 seconds.
Crack in the egg and cook to your liking, basting with the spiced oil as you go.
Warm the flatbread in a dry pan over a medium heat, then transfer to a serving plate.
Slide the egg onto the flatbread, drain the chilli and spring onions and scatter over the top. Sprinkle with the reserved coriander leaves and serve.