1.Place potato in a large saucepan; cover with cold water. Bring to the boil. Boil for 10 minutes or until tender. Drain: return to pan, mash until almost smooth. Transfer potato to a large bowl.
2.Add onion, curry paste, coriander, salmon zest and egg to potato. Season with salt and pepper. Shape mixture into 4 patties. Dust with cornflour. Place on a plate. Cover with plastic food wrap: chill for 15 minutes.
3.Heat oil in a large trying pan over low heat. Cook patties for 5-7 minutes each side or until golden. Drain on paper towels.
4.Place bread roll bases on serving plates. Top with lettuce, patty, tomato, cucumber and carrot. Top with yoghurt and sauce. Serve at once with lemon wedges.
Replace green curry paste with mild curry powder. Use a vegetable peeler to slice carrot lengthwise into ribbons. Serve with steamed greens instead of rolls and salad.