Bloom the saffron: In a small cup, add the saffron threads to 1 tablespoon of warm water.
Let it sit for 5–10 minutes. This releases color and aroma without bitterness.
Chill your glass: Fill a coupe or martini glass with ice water. A cold glass keeps the cocktail crisp and smooth.
Build the cocktail: In a shaker, add gin or vodka, lemon juice, simple syrup, rose water, and the saffron water (threads and all).
If using vermouth, add it now.
Add ice and shake: Fill the shaker with ice and shake hard for 12–15 seconds. You want everything cold and slightly aerated.
Strain: Dump the ice water from your glass. Double strain the cocktail into the chilled glass to catch saffron threads and ice chips.
Garnish: Express a lemon twist over the top to release oils, then drop it in.
Add a pinch of edible rose petals for a pretty finish.
Taste and adjust next time: If it’s too floral, cut the rose water next round. If it’s too tart, bump the simple syrup by 1/4 ounce.