Clean and dry a 750ml glass jar or bottle by washing with hot soapy water, rinsing, and air drying.

Rinse 4 to 6 jalapeños under cool running water, pat dry, and slice into thin rings, leaving seeds in place.

If using, cut 1 to 2 thin lime slices; prepare a small pinch of sea salt.

Pour out about 60 ml (1/4 cup) of tequila from the bottle to make room for ingredients.

Add sliced jalapeños to the tequila bottle using a funnel or carefully pour to avoid splashes.

Add lime slices and sea salt if using, then seal the bottle tightly and label with the start date.

Store the sealed bottle in a cool, dark place for 3 days, shaking gently once daily for even infusion.

After 3 days, open and taste; if desired heat is reached, strain the tequila through a fine mesh strainer or cheesecloth into a clean bottle.

Seal the strained tequila and store in the refrigerator for up to 3 months or freeze for up to 1 year.