Preheat the oven to 200 degrees celsius.
Layer the base of a baking dish with a layer of half the onions, over this layer half the potatoes. Sprinkle with half the garlic, stock, pepper, curry powder and drizzle a tablespoon of oil over the top.
Repeat with the second layer.
Slowly pour in some water to just come up with the bottom layer of the potatoes (about 5 - 10 mm).
Roast in the oven for about 45 minutes until the top layer is golden brown and most of the water has evaporated. Serve with your usual roast, stews, or even between a couple of slices of bread with your favourite chutney (great for when you have left overs!)