Preheat oven to 350; Spray 9-inch pie dish with cooking spray.
Melt butter for about 1 minute on high power.
In a large bowl combine butter, egg, brown sugar and vanilla. Mix until smooth.
Add the flour and salt. Stir until just combined. Don't over-mix.
Turn batter out into prepared pie dish, smoothing the top lightly with a spatula.
Bake for 10-12 minutes or until edges firm up slightly and center slightly begins to set up. It is by no means done & will be returned to oven so don't worry if it looks doughy.
Remove dish from oven. Sprinkle 3/4 cup chocolate chips and coconut.
Drizzle sweetened condensed milk then caramel sauce. (Eyeball it)
Return to oven for 25 minutes. There should be slight bubbling near the edge of the dish and the center will look more set. Watch carefully during the last 10 minutes to ensure the coconut, caramel and sweetened condensed milk don't burn. *Better to under-bake than over-bake*
Remove pie and place on wire rack to cool.
Melt 3/4 cup chocolate chips in microwave and drizzle over top. Pie doesn't have to be cool to apply chocolate.
Leave on wire rack for at least 4 hours before slicing. The interior will continue to firm up and the chocolate set.