I made a burnt sugar caramel sauce tonight that turned out beautiful. It is just what it sounds like; you make a normal caramel sauce but cook the sugar until it is past amber and getting almost black. Making this is such a high-wire act though, especially in a small batch. The difference between not dark enough, just right, and actually completely burned is just seconds. Much too fast to manage with a thermometer, especially because the temperature isn't even throughout the pan. So my question is, is there a way to slow this process down towards the end so that picking the right moment isn't so difficult? 
To get the sugar caramelized to that perfect dark brown, I start the sugar on the stove top and finish in the oven.    I start by adding a bit of water and some corn syrup (the fructose makes the brown more intense, but one can skip it) to the sugar and keep it on a medium burner until it reaches the first caramel stage, at 155°C/311°F.  As Michael notes, the sugar can go very fast from this stage to burnt.  To avoid this, I place the pan in an oven that has been pre-heated to 180°C/356°F, just above the dark caramel stage.  Checking every two minutes with an infrared thermometer (more often as it gets closer to 177°C/350°F), it's easy to get the sugar to the right temperature.  This post describes the method in more detail. 