Preparing the Oven and Pan

1. Preheat your oven to 350 °F (175 °C).
2. Line a 9×13-inch baking pan with parchment paper, leaving a slight overhang on the long sides. This makes it easy to lift out the baked bars for slicing.

Crafting the Buttery Crust

1. In a medium bowl, whisk together the flour, brown sugar, and salt until evenly combined.
2. Pour the melted butter over the dry ingredients. Use a rubber spatula or wooden spoon to stir until the mixture holds together in a soft, slightly crumbly dough.
3. Press the dough evenly into the bottom of the prepared pan, smoothing it with the back of a spoon or your fingertips. Aim for an even layer about ¼ inch thick.
4. Bake for 12–15 minutes, or until the edges begin to turn golden brown.
5. Reduce the oven temperature to 325 °F (165 °C) and let the crust rest while you prepare the filling.

Crafting the Chewy Coconut Filling

1. In a large mixing bowl, combine the sweetened condensed milk and eggs, whisking just until smooth.
2. Add the flour, brown sugar, melted butter, vanilla extract, and salt. Stir until you have a glossy, uniform batter.
3. Fold in 3 cups of the shredded coconut, ensuring every flake is coated in the custard base.

Assembling and Baking to Perfection

1. Pour the coconut mixture evenly over the pre-baked crust, spreading it gently with a spatula.
2. Sprinkle the remaining 1 cup of coconut over the top, creating a decorative, crunchy layer.
3. Bake at 325 °F for 25–30 minutes, or until the filling is set around the edges but still slightly jiggles in the center. The top should be lightly golden.
4. Cool the pan on a wire rack for at least 1 hour to allow the bars to firm up.
5. Lift the cooled bars out of the pan using the parchment overhang and place them on a cutting board. Slice into 24 squares using a sharp knife, wiping the blade clean between cuts.