Pour the coarse salt or chili-salt onto a small plate. Rub the rim of a rocks or coupe glass with the grapefruit wedge, then dip the rim into the salt to coat. Set the glass aside to dry while you mix the cocktail.

Muddle jalapeño

In a cocktail shaker, add the jalapeño slices and the agave syrup. Gently muddle 6–8 times to release the jalapeño oils and integrate them with the syrup. Do not over-muddle into a paste—just enough to bruise the pepper and release flavor.

Build and shake

Add vodka, fresh pink grapefruit juice, fresh lime juice, and ice to the shaker with the muddled jalapeño and syrup. Cap the shaker and shake vigorously for 12–15 seconds until the shaker is cold to the touch and slightly frosted.

Double-strain and serve

Place a fine mesh strainer over the prepared glass (or a separate mixing glass). Strain the cocktail from the shaker through the strainer to catch jalapeño bits and pulp. If you prefer a slightly lighter drink, top with 1 oz club soda. Add fresh ice to the glass if desired.

Garnish

Garnish with the reserved pink grapefruit wedge and/or a grapefruit peel twist. If you kept seeds in the jalapeño, consider a thin jalapeño slice on top for visual heat.

Adjust heat and sweetness

Taste and adjust: if the cocktail is too spicy, add 0.25–0.5 oz more agave syrup and stir gently. If it needs more acidity, add another 0.25 oz lime juice and briefly stir.