Preheat the oven to 325°F. Place the sugar in a 9-by-13-inch glass or ceramic baking dish. I actually used a smaller dish because it was what I had - around 8-by-10. As I understand it, water will evaporate from the sugar as a byproduct of caramelization, so you'd want a wider pan to encourage this evaporation and reduce clumpiness in the resulting sugar. However, my smaller pan worked fine. Also, avoid metal baking pans - they conduct heat more rapidly, which will make the sugar more likely to liquefy at the edges instead of slowly roasting.

Roast sugar, stirring every 30 minutes or so to evenly distribute the toastier parts of the sugar. After about 2 hours, the sugar should darken to a light sandy brown color, with a texture that is coarser than white sugar, similar to turbinado.

Cool sugar away from any sources of moisture or steam until completely cool. Stella says it will take an hour, but my sugar took maybe 2 hours to fully cool, plus I stirred it a few times to help release heat. The longer cooling time could have been due to my smaller pan and the sweltering Chicago heat wave. If the sugar is very clumpy after cooling, that's ok - just pulse it in a food processor until fine and powdery.

Store for up to a year in an airtight container at room temperature, and use in place of granulated white sugar.