Preheat your oven to 350°F (175°C) to ensure the bars bake evenly.
Line your 9x13 inch baking pan with parchment paper, leaving some overhang for easy removal.
In a mixing bowl, combine the melted butter and brown sugar. Mix until well combined. Then, add the graham cracker crumbs and stir until the mixture resembles wet sand.
Evenly press the graham cracker mixture into the bottom of the prepared baking pan.
Sprinkle ½ cup of shredded coconut over the graham cracker base, followed by the white chocolate chips, bittersweet chocolate chips, and semisweet chocolate chips.
Evenly distribute the chopped, toasted pecans over the layers.
Pour the sweetened condensed milk evenly over the top of the layered ingredients.
Finally, sprinkle the remaining ½ cup of shredded coconut over the top.
Bake in the preheated oven for about 25-30 minutes, or until the edges are golden brown and the center is set.
Allow the bars to cool in the pan for at least 15 minutes before using the parchment paper to lift them out. Let them cool completely on a wire rack before cutting into squares.
