Armagnac is a French brandy produced in Gascony, France which is southeast of Bordeaux. This smooth tasting brandy is aged in oak for up to 40 years. The production of this brandy dates back at least 200 years before it's competitor Cognac.
Typically this is a sipping spirit but it can be used in cooking for dishes such as steak au poivre or in numerous desserts and baked good. Look for Armagnac in a good, well-stocked liquor store.
You can purchase this brandy in well-stocked liquor stores OR you can purchase online at Bevmo.com.
If you don't have Armagnac you can substitute one of these alternatives: