Place the lamb in a big jar and use ground black pepper to season well. Add the curry powder with the yogurt and 1/2 tbsp and mix well to mix.
In a big non-stick casserole, heat half the oil. Fry the onion wedges for 4-5 minutes over elevated heat or until slightly brown and soft. Tip on a tray, laid aside and heat back the bowl.
Stirring occasionally, add the residual oil, chopped onions, garlic, ginger and chili, cover and boil for 10 minutes or until very tender. Remove the flap, boost warmth and boil for 2-3 more minutes or until the peppers are mixed with purple–this will add loads of flavor, but make sure that they are not burned.