Preheat oven to 350 degrees.

In a standing mixer, beat the butter, sugar and egg yolks together just until combined. Add the flour and salt, and mix until the crumbles start to form. Press the dough evenly into an 8″ x 8″ or 9″ x 9″ glass or metal pan. Bake in the oven for 15 minutes.

In a medium saucepan over medium heat, mix the maple syrup, brown sugar, sweetened condensed milk, and butter together. Cook until the mixture starts to bubble then remove from heat.

Pour the mixture into the crust and return to the oven for 25 minutes. Open the oven and sprinkle the top of the bars with the coconut flakes and bake for another 2-3 minutes or until the coconut begins to brown. 

Remove from the oven, and let cool on the counter for at least 2 hours before dusting with powdered sugar and serving.