"This recipe uses Venezuelan frozen passion fruit pulp, which I can find in Latino markets. It's very good. Take it out of the freezer and let it thaw before you use it. Garnish with a dollop of fresh whipped cream and top with fruits like kiwi and strawberry plus passion fruit pulp and seeds."
Heat a saucepan over medium-low heat. Combine passion fruit pulp, sugar, and lime juice in the hot pan. Cook and stir until sugar dissolves, about 5 minutes. Remove from heat; let cool completely.
Sprinkle gelatin over water in a bowl. Let soften, about 5 minutes.
Fill a large bowl with ice and water.
Place softened gelatin in the top pan of a double boiler over simmering water. Stir frequently, scraping down the sides with a rubber spatula to avoid scorching, until dissolved, 2 to 4 minutes. Add lime-passion fruit mixture. Stir constantly until hot, 1 to 2 minutes more. Remove from heat. Transfer pan to the ice water bath. Let cool, about 30 minutes.
Mix egg whites and cream of tartar together in a large bowl using an electric mixer until stiff peaks form. Gently fold egg white mixture, 1 spoonful at a time, into the cooled passion fruit mixture using a spatula. Spoon mousse carefully into 10 stemmed glasses or ramekins. Cover with plastic wrap and chill in the refrigerator until set, at least 6 hours.
Let mousse stand at room temperature for 20 minutes before serving.