Preheat the oven to 350°F (175°C). Line an 8x8 inch baking pan with parchment paper.

In a mixing bowl, combine flour, brown sugar, melted butter, and salt. Mix until crumbly.

Press the mixture evenly into the bottom of the prepared baking pan.

Bake in the preheated oven for 10 minutes, then remove and let cool slightly.

In a medium saucepan over medium heat, combine sweetened condensed milk, brown sugar, and cubed butter.

Stir continuously until the mixture comes to a gentle boil and thickens, about 5-7 minutes.

Remove from heat and stir in the shredded coconut until well combined.

Pour the caramel mixture over the baked base and spread evenly.

Return the pan to the oven and bake for an additional 15 minutes, until the top is golden.

Remove from the oven and let cool completely in the pan on a wire rack.

Once cooled, lift the bars out using the parchment paper and cut into squares.