Combine 1 cup water, 1 cup granulated sugar, and the scooped insides of about 6 ripe passion fruits in a saucepan over medium high heat. bring to a boil, stirring until sugar is fully dissolved. Reduce heat to low, simmering for 20 minutes, uncovered. Remove from heat, let cool, then transfer to an airtight container and refrigerate. Do not discard passion fruit seeds! That's what makes the syrup so pretty.
Combine all ingredients except egg white in a cocktail shaker over ice. Shake until thoroughly chilled.
Strain contents of shaker into a standby glass, dump ice, put cocktail mixture immediately back into chilled shaker and add egg white. Shake vigorously for about thirty seconds or until egg white is foamed.
Pour (don't strain) contents into a coupe glass.
Garnish with a floating slice of passion fruit and a passion fruit leaf and vine tendril, if you've got them.