Choose a rocks glass or coupe and chill it by filling with ice and setting aside for 2–3 minutes. Meanwhile, pour the kosher or flake sea salt onto a small plate. Run a lime wedge around the rim of the glass to moisten, then dip the rim into the salt to coat. Discard the chilling ice and set the glass aside.

Combine ingredients

In a cocktail shaker, add 2 oz blanco tequila, 0.5 oz reposado tequila, 1 oz fresh lime juice (juice of about 1 medium lime), 0.75 oz Cointreau, 0.5 oz agave syrup, and 2 dashes orange bitters.

Add ice and shake

Fill the shaker with ice (about 1 cup) until roughly three-quarters full. Secure the lid and shake vigorously for 10–15 seconds, until the outside of the shaker is frosty and well chilled.

Strain

Fine-strain the cocktail into the prepared chilled glass over one large ice cube or without ice if serving straight up, depending on preference.

Garnish and finish

Garnish with a lime wheel or wedge on the rim. Sprinkle the fine lime zest over the surface if using. If using smoked salt or a mezcal rinse for the optional finish: either lightly dust a tiny pinch (about 1/4 tsp) of smoked salt on top or rinse the chilled glass before salting the rim with 1/4 tsp mezcal, pouring it in, tipping to coat, then discarding excess and salting the rim as instructed above.