Combine all the ingredients except the butter and salt in a small sauce pot and reduce by half.
Strain off the wine and return it to the pot and reduce it until it has the consistency of syrup.
Whisk in the butter a few pieces at a time, allowing the butter to melt by 80% before adding more and continue to do this until all the butter has been mounted into the reduction.
Whisk in salt and serve with fish or steak