Preheat oven to 350 degrees
In a large bowl mix the dry ingredients: flour, brown sugar and salt. Then, stir in 1 cup melted butter. Pour over onto prepared pan. Press onto bottom of prepared pan. Bake until light brown, 12-15 minutes. Allow the crust to cool 10 minutes.
Reduce oven setting to 325°.
In a large bowl, whisk the eggs, sweetened milk, flour, brown sugar, butter, vanilla, and salt until well blended. stir in 3 cups coconut.
Pour over crust; sprinkle with remaining coconut. Bake until light golden brown, 25-30 minutes. Cool in pan on a wire rack. Lifting with parchment paper, remove from pan. Cut into bars.