1.Stir sugar and the water in medium saucepan over low heat until sugar dissolves; bring to the boil. Boil, uncovered, without stirring, about 10 minutes or until mixture is a dark caramel colour. Remove from heat; allow bubbles to subside.
2.Meanwhile, arrange orange slices, overlapping slightly, on large heatproof platter; sprinkle with spices.
3.Pour half the toffee over oranges; pour remaining toffee onto greased oven tray. Stand oranges at room temperature about 2 hours or until toffee dissolves and forms a sauce over oranges. Allow toffee on tray to set at room temperature.
4.Break set toffee into pieces; sprinkle over oranges.
When you think the toffee syrup has almost reached the colour we suggest, quickly remove the pan from the heat, remembering that the syrup will continue to cook and darken during this time. Let the bubbles subside, then drop a teaspoon of the syrup into a cup of cold water. The toffee should set the instant it hits the cold water; lift it out and break it with your fingers. If the toffee needs to be harder, then return the mixture to the heat and cook a little more. This test is easy, but a candy thermometer removes all the guess work for you. If you have a candy thermometer, boil the mixture until it reaches 138°C/280°F.