In a medium size sauce pan combine the hot sauce, apple cider vinegar, and sugar and bring to a simmer over medium heat. Reduce the heat to medium low and cook for until the sauce is slightly reduced, about 12 to 15 minutes.
Using a hand blender, slowly blend in the butter until the mixture is smooth.
The sauce can be served immediately or stored in the refrigerator in an air tight container for several months. The sauce can be reheated over a low heat while constantly whisking to reincorporate the butter.
Yield: about 3 cups