Step 1: Add gelatin and ¼ cup room-temperature water to small bowl; let sit until gelatin softens, about 5 minutes. In medium saucepan over medium-high heat, stir together passion fruit pulp, sugar and gelatin mixture. Cook, stirring occasionally, until mixture is thoroughly combined and smooth (mixture should not come to a boil). Remove from heat; cool completely. Stir in condensed milk.

Step 2: Meanwhile, in clean mixing bowl, using electric mixer, beat egg whites until stiff (peaks of egg whites will not droop, and egg whites will not move when bowl is tilted).

Step 3: Stir 1/3 egg whites into cooled passion fruit mixture until combined. Using spatula, gently fold in remaining egg whites until combined. Divide mousse evenly among clear glass serving cups; cover. Refrigerate mousse until well chilled, at least 2 hrs.

Step 4: Serve chilled. Garnish with mint, if desired.