Pour tajín (and coarse salt if using) onto a small plate. Run the lime wedge around the rim of a rocks or coupe glass, then dip the rim into the tajín to coat evenly. Set glass aside to dry for 1–2 minutes.

Infuse & Build

Muddle jalapeño

In a shaker, add 2 of the jalapeño slices (reserve one for garnish). Gently muddle 6–8 times to release aroma and some heat; avoid pulverizing to keep bitterness down. If you prefer milder spice, remove seeds before muddling.

Add liquids and ice

Add the reposado tequila (2 oz), triple sec (1 oz), fresh mango juice (3 oz), margarita mix (1 oz), fresh lime juice (0.5 oz), and agave syrup (0.25 oz, optional) into the shaker. Fill the shaker about two-thirds with ice (approximately 1 cup).

Shake

Secure the shaker and shake vigorously for 12–15 seconds until the outside of the shaker is well chilled (this both chills and slightly dilutes the cocktail).

Strain & Serve

Double strain

Using a Hawthorne strainer and a fine-mesh (or second) strainer, double-strain the cocktail into the tajín-rimmed glass over fresh ice (if serving on the rocks). Double straining removes jalapeño bits and excess pulp for a clean presentation.

Garnish

Garnish with the reserved jalapeño slice and a mango slice or wheel on the rim. Optionally add a small lime wedge. Serve immediately.