Line a greased 9x13-in metal baking pan with parchment paper. Spray with more non-stick spray. Preheat the oven to 350°F.
In a medium bowl, combine all the ingredients for the crust until the dough is the texture of a coarse meal. Lightly press the mixture into the prepared pan. Bake for about 15 minutes and remove from the oven to cool.
Meanwhile, in a large bowl, combine the sugar and cornstarch. Whisk in the eggs one at a time. Stir in the passion fruit purée and lemon juice until well-combined. Pour mixture onto the crust.
Bake for 20 minutes or until the filling is set. Let cool on a wire rack. Cover with plastic wrap directly on the surface of the filling and refrigerate for 2 hours. Cut into triangles with a large knife. Top with Tajín and mint leaves, and serve with a side of Pop Rocks. *Please note that Pop Rocks pretty much dissolve on contact with the surface of the bars, so it's best to sprinkle it on right before eating your bars.