Pisco is brandy made from distilled wine. No, it's not Cognac. The difference being that Cognac must be made in the Cognac region of France. Pisco is made in Peru and Chile and, unlike French Brandy, is not aged in wooden barrels; rather, it may only be "rested" in a neutral, glass or stainless steel container -- the resulting spirit being clear. Like Bourbon in the U.S.A. or Tequila in Mexico, there are strict laws that regulate its production, and those laws vary based on its country of origin (Peru or Chile). Piscos are usually either categorized as being of the "non-aromatic" or "aromatic" variety, referring to the type of grape it is made from. A couple designations you may see at your local spirit shop are:"Acholado" (made from a combination of different grapes); "Quebranta" (a traditional, non-aromatic variety popular in Peru), and "Mosto Verde" (Pisco made from a distillate of only partially-fermented grape juice (sweeter and typically pricier than more traditional varieties).
And now for the recipe. You'll need:
2 oz Pisco
3/4 oz simple syrup (1:1 water&sugar)
1/2 oz egg white
1/2 oz lemon juice
1/2 oz lime juice
First: Combine all ingredients into a cocktail shaker (w/o ice, to froth the mixture) and shake hard 10-15 seconds.
Then: Add ice to the shaker and shake (a second time) 20-30 seconds.
Finally: Strain into a chilled cocktail glass and sprinkle a few dashes of Angostura bitters over the foam-head.