Fry the beef and onion in a large saucepan for 5 minutes or until evenly browned, stirring to break up the meat. Add the potatoes, garlic, ginger, spices and chilli and fry for 2 minutes, stirring. Add the tomatoes with their juice and the stock and season with pepper. Bring to the boil, then cover and simmer for 20 minutes, stirring occasionally.
Meanwhile, to make the cucumber raita, mix the yoghurt, cucumber and mint together with a little pepper. Spoon into a small bowl and chill until required.
Stir the baby spinach into the curry and heat through for about 1 minute, then add a little more pepper. Spoon the curry onto warmed plates and sprinkle with fresh mint leaves. Serve immediately, with the chilled cucumber raita.
If you prefer, you can cook the curry in the oven. Brown the beef and onion in a flameproof casserole dish, then add the other ingredients and bring to the boil. Cover and cook in a preheated 180ºC oven for 1 hour. Add the spinach, toss with the meat, then cover and return to the oven to cook for 10 minutes. * For a fruity curry, you can add 1/2 cup sultanas and 1 sliced dessert apple with the potatoes. Omit the spinach. Garnish the curry with 1 diced banana tossed with the juice of 1/2 lemon and 2 tablespoons chopped fresh coriander.
A raita or sauce of yogurt, cucumber and mint is often served with curries to act as a cooling agent against the heat of the chillies and spices. Yogurt is also extremely nutritious – it is a valuable source of calcium and it provides useful amounts of phosphorus, the B vitamin riboflavin and vitamin B12. Live yogurt also provides beneficial bacteria that can help to maintain a healthy digestive tract.