Step 1: Preheat and Prepare the Baking Pan

1. Preheat your oven to 350°F (175°C).
2. Line an 8×8-inch square baking pan with parchment paper, leaving an overhang on two sides for easy removal.

Step 2: Make the Shortbread Crust

1. In a mixing bowl, combine the flour, sugar, and salt.
2. Add the cold, cubed butter and use a pastry cutter or your fingers to mix until the dough resembles coarse crumbs.
3. Press the mixture evenly into the bottom of the prepared pan. Use the back of a spoon or your fingers to compact it firmly.
4. Bake for 15-20 minutes, or until the edges are lightly golden. Remove from the oven and let cool slightly.

Step 3: Prepare the Mango Filling

1. In a blender or food processor, purée the mango until smooth. If using frozen mango, thaw it first and drain excess liquid.
2. In a large bowl, whisk the eggs and sugar until well combined. Add the mango purée, lime juice, flour, and salt. Whisk until smooth and free of lumps.

Step 4: Assemble and Bake

1. Pour the mango filling over the partially baked crust, spreading it evenly.
2. Bake for 25-30 minutes, or until the filling is set and no longer jiggles in the center.
3. Remove from the oven and let cool completely at room temperature.

Step 5: Chill and Serve

1. Refrigerate the mango bars for at least 2 hours to firm up.
2. Lift the bars out of the pan using the parchment overhang. Cut into 16 squares. Dust with powdered sugar or top with toasted coconut and lime zest, if desired.