Preheat the oven to 375°F. Spread ½ cup sweetened flaked coconut in a single layer. Roast in the oven, stirring often until golden around 5 minutes. Set aside to cool.
Spray a metal non stick 13 x 9-inch rimmed pan with cooking spray. Set aside.
In a large mixing bowl mix together the graham cracker crumbs, remaining coconut, milk chocolate toffee bits and milk chocolate chips.
On the stovetop in a heavy bottomed saucepan melt together the mini marshmallows, sweetened condensed milk and butter. Heat over medium until the marshmallows are completely melted.
Pour into the mixing bowl. Use a large spoon or spatula working quickly to mix until combined. Press evenly into the pan.
To make topping: In a microwave safe bowl, melt together the milk chocolate chips and heavy cream, heating in 20 second increments stopping to stir each time. Repeat until smooth.
Spread the melted milk chocolate over the bars and sprinkle with toasted coconut.
Chill completely then cut into bars.