Place the 2 hulled fresh strawberries in a cocktail shaker or sturdy mixing glass. Add the agave syrup (if using). Using a muddler or the back of a spoon, gently muddle the strawberries until broken down and they release their juices but not completely puréed — about 8–10 medium presses.

Combine ingredients

Add 2 oz reposado tequila, 0.75 oz Cointreau, 0.75 oz fresh lime juice, and 2 oz mango purée into the shaker with the muddled strawberries.

Add ice and shake

Fill the shaker with about 1 cup of ice (enough to chill and slightly dilute). Secure the shaker lid and shake vigorously for 12–15 seconds until the outside of the shaker is cold and slightly frosted.

Prepare glass

Fill a rocks glass or coupe with fresh ice (about 1 cup if using a rocks glass). If desired, run a lime wedge around the rim and dip in sugar or leave plain.

Strain and serve

Double-strain (using a fine mesh strainer over the shaker's built-in strainer) into the prepared glass to remove seeds and large pulp. If you prefer a slushy texture, pour unstrained.

Garnish

Thread a strawberry slice and mango wedge onto a pick or rest them on the rim. Add a lime wheel if desired. Serve immediately.