No Egg Whites? Give Your Cocktail A Frothy Foam Using Half-And-Half
If you were asked to name a drink made with eggs, chances are that eggnog might be one of the first ones to come to mind unless you're a fan of advocaat, rompope, or similar egg-based liqueurs. If the hypothetical questioner were to narrow it down to egg whites alone, though, then you might recall certain cocktails such as sours, flips, and fizzes that are typically topped off with an eggy froth. (Not to be confused with the apocryphal Anglo-Saxon Eggfroth the Unbeaten, since we made him up ourselves.)
Maybe you're not in touch with your Inner Rocky, though, so you don't care to consume raw egg white in your cocktail (it's mostly safe, but salmonella is still a possibility). It's also possible that you just made an angel food cake and have nothing left in the fridge but yolks. Whatever the reason you'll need to go eggless, you have some alternatives open to you should you feel that your pink lady is incomplete sans froth. One of these involves using a tablespoon of half-and-half, which is simply shaken up with the other drink ingredients. In the words of the late Macho Man Randy Savage, "The cream rises to the top (oh yeah)." So once the rest of the liquid settles, your cocktail will be capped off with a little milky foam.
Other egg white substitutes are suitable for vegans
One pretty big reason why you might want to eschew eggs in your cocktails is because you are following a vegan diet. In this case, you may have heard people sing the praises of aquafaba, which is the liquid drained from a can of chickpeas. If you eat a lot of chickpeas and can tolerate a slightly beany taste (aquafaba isn't entirely flavorless), it makes for a pretty decent egg white substitute in cocktails as well as in baking.
If you don't want to open a can of beans every time you want to mix a drink, though, you may find that using an egg substitute such as chia seeds mixed with water works better for you since you can just make a micro-batch as needed. Xanthan gum, too, can also help foam up your drink, as can a soy protein powder called Versawhip. If you prefer not to add bean juice, seeds, or stuff that sounds like a science experiment to your drink, though, here's a tip: Mix your drink in a blender or with a handheld milk frother, and it will foam all on its own. Drinks made with orange or pineapple juice or coffee seem to be especially cooperative self-foamers, although you will, of course, need to drink up before they deflate or else accept that your drink will be slightly less frothy the longer it sits.