1. Preheat the oven to 350. Spray a 8X8 pan and line with parchment leaving an overhang.
2. To make the crust: Cut the butter into tablespoon-sized pieces. In a saucepan over medium heat, melt the butter while stirring constantly. The melted butter will foam a bit, then the foam will subside. Keep cooking the butter until the milk solids turn golden brown, 7 to 10 minutes. Take the butter off the heat and pour it and all the browned bits from the pan into a heat-safe bowl to cool slightly.
3. When the butter has cooled, add the sugar, vanilla, and salt. Add the flour and mix until just incorporated. Press the dough evenly into the bottom of the prepared pan.
4. Bake the crust for 20-22 minutes, until it is golden brown. Lower the temperature to 300.
5. Make the filling-stir the sugar and flour together, whisk in the eggs then the passionfruit, lemon juice and zest. Pour over the crust and bake for 25-27 minutes, until the filling stops jiggling and its barley set. Let cool to room temperature. Then refrigerate for two hours before cutting.
6. Cut the bars into square or triangles and dust with confectioners’ sugar just before serving. Store leftover bars in the fridge.

* To make the passionfruit juice place a strainer over a small bowl. Scoop out the passionfruit and place into the strainer with a spatula extracting as much of the juice as possible.