Step 1

Combine the sugar and butter in a medium sized saucepan. Melt on medium heat, then bring to a bubbling boil, letting the sugar darken somewhat. Do not boil until it's hard candy however.

Step 2

Once the butter and sugar have started bubbling, let boil for another 2-3 minutes, then slowly and carefully pour in the hot water. It most likely WILL SPIT so be careful!

Step 3

Stir together and bring to a boil again.

Step 4

To thicken, combine the cornstarch and cold water, then whisk into the boiling brown sugar mixture. Cook until it thickens up slightly then remove from the heat.

Step 5

Serve warm.