Vietnamese Caramel Sauce (Nuoc Mau) is made by cooking cane sugar until it forms an amber-colored liquid that thickens over time. It is used as a seasoning for braised dishes (such as thit kho), grilled meats, and many other Vietnamese dishes.
(Note: The caramelization process happens quickly. Read the direction first before starting. Do not leave the stove unattended and have the water pre-measured before starting). Turn the stovetop to medium heat, and sprinkle sugar evenly over the surface of a small saucepan. Let it sit for 1-2 minutes without stirring.
Once the sugar starts to melt, use a whisk or rubber spatula to stir constantly for 4-5 minutes (times will vary depending on your stovetop). You will see the sugar turning from clear to champagne yellow to a dark amber color.
As soon as it starts smoking, immediately turn off the heat, pour in the water, and stir until the sugar is dissolved.
Once it has cooled down, store it in a jar with a lid in the fridge for up to 3 months.