In a small, heavy saucepan, mix together the Balsamic and honey or sugar. Bring to a boil, reduce to a good simmer and until the mixture has thickened slightly and coats a spoon. Generally, this is reduced by about 1/2 but can vary depending on the Balsamic Vinegar you start with and how thick you wish the Balsamic Reduction to be.. Watch carefully at the end; this will take several minutes.

Remove from heat, let cool slightly and whisk in butter. Cool to room temperature.

Notes:

• Various herbs and seasonings may be added; see the body of text.
• If your Balsamic Reduction becomes too thick, thin with a bit of warm water. If it thickens in the fridge from the cold, place it in a bowl of very hot water until it warms a bit.
• Balsamic Reduction will keep for weeks, almost indefinitely, in the refrigerator.