Grease a 9x13-inch baking dish with cooking spray, or use a parchment paper sling to make it easier to get the bars out.
Sprinkle graham cracker crumbs into the bottom of the pan. Pour melted butter over the graham cracker crumbs. Press into the bottom of the pan to form a crust
Sprinkle butterscotch chips, chocolate chips, walnuts and sweetened coconut on top of the graham cracker crust.
Drizzle sweetened condensed milk on top.
Bake for 25 minutes until golden brown on top. Allow the bars to cool for 1 hour before slicing.
Notes
Storing: Keep the cookie bars in an airtight container at room temperature for up to 5 days. It isn't necessary to refrigerate them unless you prefer them on the firmer side.Freezing: The dessert bars will keep frozen for up to 3 months. Before storing, chill them on a baking sheet to firm them up before layering them in an airtight container between squares of parchment paper. Or, you can wrap them individually.