This is one of my favorite drinks, period, and I include it here as a way to make excellent use of the egg whites from egg yolk pasta. The better the whiskey, the better the cocktail. These can be made in batches in a large measuring cup and poured as needed for multiple guests; use an immersion blender for thorough mixing. I prefer an equal mixture of lemon and lime juice for the citrus. To make simple syrup, combine 1 cup/240 milliliters sugar and 1 cup/240 milliliters water in a Pyrex measuring cup and microwave for 2 to 3 minutes, until the sugar is dissolved. This will keep for a month refrigerated. Simple syrup can be enhanced by loading the sugar water with lemon and lime zest before heating. Good thing you saved those egg whites.