Place the potatoes in a pan of cold, salted water. Bring to the boil and cook for 10 minutes. Drain and allow to air-dry for 5 minutes.
Preheat the oven to 200°C fan.
Spray a large ovenproof dish with low-calorie cooking spray. Add the potatoes, sausages, onions and peppers. Spray with low-calorie cooking spray and season with salt and pepper. Roast in the oven for 40 minutes, stirring halfway through.
While the traybake is in the oven, whisk all the curry sauce ingredients together in a small bowl.
After 40 minutes, add the broccoli florets, peas and curry sauce. Stir well so the curry sauce coats the sausages and vegetables, and return to the oven for 15-20 minutes until the sausages are browned and the sauce is bubbling.
Sprinkle the coriander on top and serve with a dollop of fat-free Greek yoghurt (optional).