Mix the lime juice, mezcal, Angostura bitters, agave syrup, and egg white in a cocktail shaker and shake for one minute, until frothy.
Fill the shaker with ice and shake for an additional one minute.
Strain through a fine-mesh sieve into a serving glass. Garnish as desired and enjoy immediately.
Notes
It's all about the strain - Make sure to strain your cocktail well using a fine-mesh strainer or a Hawthorne strainer. This will ensure that your cocktail is the best texture and will make sure there are no unwanted bits.Use fresh ingredients - Always use fresh ingredients, such as citrus juice, to get the best flavor. Avoid using bottled juice, which can have a flat taste and may contain preservatives.Double shake it - For the ultimate sour cocktail, start with a dry shake that excludes the ice, then add the ice and shake it again. This will give your sour cocktail the best texture without getting diluted.Garnish with a citrus twist - A citrus twist is a classic garnish for a sour cocktail. Use a vegetable peeler or a sharp knife to cut a long, thin strip of citrus peel and twist it over the cocktail to release the oils and add a fresh aroma.Chill your serving glass - To make the cocktail extra frosty, place your cocktail glasses in the freezer 30 minutes before making your Mezcal Sour. This ensures that your cocktail stays super cold and doesn't instantly come to room temperature.