Morning,Collin. Yes, egg whites add so much goodness to a cocktail(flip or sour). The whites contribute a unique, almost sublime mouthfeel, along with the subtle softening of the spirit used as base. Whiskey and Pisco Sours are traditional and fantastic, but why not try a Cynar Flip? Cynar is an artichoke-based liquor popping up more and more frequently in Seattle's top echelon of watering holes. The flavor of Cynar is bitter/herbal/sweet and each of those notes are not shy about making their presence known. Add an egg white and the concoction becomes softer, allowing your palette to easier identify the more subtle notes of such a unique spirit.
Some tips when using egg whites-
Whip up the egg separately from your other ingredients and set aside while combining your base(ie. Bourbon), citrus(lemon juice) and sugar(simple syrup).
Then add the "meringue"(the egg white should be thick and frothy-a dense foam) and gently mix. My personal preference for whipping up the egg white is to use a Hawthorn spring(pull it off from your strainer and place it in the pint glass along with the egg). Then shake vigorously with metal capped over the glass(the basic Boston Shaker set up.)