Technique
Shake the passion fruit pulp, lemon, and syrup with ice to chill and combine them before straining over fresh ice. Add the sparkling water only after shaking, then stir once from the bottom so it stays lively.
A tropical, exotic non-alcoholic drink bursting with the intense sweet-tart flavor of passion fruit and fresh lemon.

TonicDB editorial guide
Passion fruit brings concentrated tropical aroma and its own sharp acidity, so this lemonade is more intense than a lemon-only version. Simple syrup connects the two tart fruits, while sparkling water opens the mixture and carries the aroma.
Shake the passion fruit pulp, lemon, and syrup with ice to chill and combine them before straining over fresh ice. Add the sparkling water only after shaking, then stir once from the bottom so it stays lively.
A tall glass leaves room for ice and the four-ounce soda finish. If you garnish with a passion fruit half, set it securely at the rim rather than dropping a large shell into the drink.
Fresh passion fruit ranges from sharply tart to quite sweet, and packaged pulp may already contain sugar. Taste the pulp first and adjust the syrup before shaking; otherwise the fixed three-quarter ounce can push the drink too far in either direction.
For visible seeds and a more rustic texture, fine-strain only part of the pulp and spoon a little fresh pulp over the finished drink. For a still lemonade, replace the sparkling water with cold water and stir more thoroughly.
These notes explain how to execute and adapt the recipe shown above. Ingredients and serving traditions vary, so taste and adjust thoughtfully.
Contributed by @alfg