Pour all ingredients into shaker with ice cubes. Shake vigorously. Strain into chilled cocktail glass, or "on the rocks" into a traditional clay or terracotta mug.
The Illegal is an IBA official cocktail.[1] This cocktail is named after the mezcal brand Ilegal Mezcal, which is one of its key ingredients. Mezcal is a type of Mexican distilled spirit made from agave plants, similar to tequila but with a distinct smoky flavor.