Prep the glass: Choose a sturdy 12–16 oz glass. Add the mint leaves and 2–3 lime wedges to the bottom.
Add sweetener: Spoon in your sugar or simple syrup.
If using granulated sugar, it will dissolve as you muddle and stir.
Muddle gently: Use a muddler or the back of a wooden spoon to press the mint and lime together. Aim for 6–8 light presses. Do not shred the mint—you want the oils released, not bitterness.
Squeeze and adjust: Add another wedge and squeeze in more lime juice to taste. Remove any large rind pieces if you prefer a cleaner sip.
Fill with ice: Add ice almost to the top.
Crushed ice gives a frostier, quick-chill effect; cubes dilute more slowly.
Top with bubbles: Pour in the sparkling water or club soda. Give it a gentle stir from the bottom up to mix without killing the fizz.
Finish and taste: Add a tiny pinch of salt if using—it brightens everything. Taste and adjust sweetness or lime as needed.
Garnish and serve: Tuck in a mint sprig and a lime wheel.
Serve immediately while it’s icy and bubbly.