Place the lamb in a large bowl, heat the oil in a pan, sauté the onions. Add the curry paste, cook for a minute of two - cool. Stir the mixture through the minced lamb plus the scallions and seasoning. Shape into 4 lamb burgers (they could be frozen also at this stage).
Heat a pan, grill or barbecue. Cook the lamburgers for five to six minutes on each side. Meanwhile mix the soured cream with the curry paste, seasoning, scallions, sugar and vinegar. Taste for seasoning. Serve the lamb burgers, on a burger bun, with a spoonful of the dressing, salad and some finely chopped red onion and fresh chilli (optional).