Mash the potatoes with butter and milk. Season with salt & pepper.
Brown the meat in a large skillet, and put in colander to drain.
Heat the oil in a skillet and add the onions and garlic. Cook, stirring occasionally until they are wilted. Add the curry powder, cumin and coriander and cook briefly, stirring.
Add the meat, salt, pepper, the ketchup, broth and sugar. Cook, stirring occasionally, about 20 minutes.
Put mixture into a baking dish and top with the defrosted frozen peas, then the mashed potato mixture. Smooth over the top. Dot with a tablespoon of butter. Run the mixture under the broiler until it is golden brown.