Chill coupe glass with ice water. Build mezcal, cardamom syrup, lemon and bitters in shaker tin. Add egg white in a smaller tin. Combine tins together with 2 ice cubes and dry shake vigorously for 10 seconds. Uncap, add ice, cap and seal again and hard shake for 10-12 seconds. Dump your ice water from your coupe and double strain with a Hawthorne strainer through a fine strainer into your chilled coupe.