Adjust oven rack to center position and preheat oven to 300°F (150°C).
Pour sugar into a 9- by 13-inch glass or ceramic baking dish.
Toast until the sugar turns ivory, about 1 hour.
Stir thoroughly and continue roasting, pausing to stir every 30 minutes.
Continue toasting and stirring every 30 minutes until the sugar has darkened to the desired degree, from a light beige to the color of traditional brown sugar, between 2 and 4 hours more.
When the sugar has finished toasting, set aside and cool to room temperature, stirring from time to time to speed the process and allow for continued evaporation of steam.
Alternatively, the cooling process can be sped along by pouring the sugar into a large, heat safe container.
Once fully cool, transfer to an airtight container and store as you would plain white sugar.
