Methods

1. To make the syrup, pound the saffron into a fine powder using a mortar and pestle. Add the saffron and sugar to a medium saucepan. Add the water to the mortar and pestle to get any last bits of saffron off and pour into the pan with the saffron-sugar mixture. Bring to a boil over medium high heat and cook, stirring occasionally, until the sugar is dissolved. Turn off the heat, let cool completely, and transfer to a jar or bottle. Store in the refrigerator for up to 3 months. 
2. To make the cocktail, place the gin, saffron simple syrup, lemon juice, and egg white into a cocktail shaker. Seal and dry shake for 30 seconds. Unseal, add a big handful of ice, cover again, and shake vigorously until the outside if the shaker feels icy, 15 to 30 seconds. 
3. Strain the cocktail into one or two glasses (ice is optional). Top with a splash or two of club soda, garnish with a few strands of saffron and enjoy immediately.