Rub the rim of a rocks or coupe glass with the lime wedge. On a small plate, combine the coarse salt and optional fine sugar; dip the moistened rim into the salt/sugar mixture to coat evenly. Set the glass aside.

Mix Cocktail

Combine ingredients

Fill a cocktail shaker about two-thirds full with ice. Add 2 oz plata tequila, 1 oz Cointreau, 1.25 oz Guava Reàl, and 1 oz fresh lime juice. If you prefer a slightly sweeter drink, add 0.25 oz agave syrup.

Shake

Secure the shaker and shake vigorously for 12–15 seconds, until the shaker is well chilled and slightly frosted. This both chills and dilutes the cocktail to the right balance.

Strain

Double-strain (using a Hawthorne and fine mesh strainer if available) into the prepared rimmed glass over fresh ice if serving on the rocks, or neat into the glass if serving straight up.

Finish & Serve

Garnish the cocktail with a lime wheel on the rim and, if available, a thin slice of guava floated on top or skewered. Serve immediately.