Preheat oven to 350F (175C). Spray a 9-inch pie dish very well with cooking spray.

In a large, microwave-safe bowl, melt the butter (about 1 minute on high power).

Wait a moment before adding the egg to avoid scrambling. Add the egg, brown sugar, and vanilla. Whisk until smooth.

Add the flour and salt. Stir until just combined; do not overmix.

Turn the batter out into the prepared pie dish, smoothing the top lightly with a spatula. Bake for 10-12 minutes, or until the edges begin to firm up slightly and the center has started to set.

Remove the pie dish from the oven and evenly sprinkle the 0.75 cup of chocolate chips over the crust.

Evenly sprinkle the shredded coconut over the chocolate chips.

Evenly drizzle the sweetened condensed milk over the coconut (eyeball it).

Evenly drizzle the caramel sauce over the sweetened condensed milk (eyeball it).

Return the pan to the oven and bake for about 25 minutes, or until there's slight bubbling near the edge of the dish and the center looks more set. The pie will firm up more as it cools. In the last 10 minutes of baking, watch carefully as the coconut, caramel, and sweetened condensed milk can burn.

While the pie cools, melt the 0.75 cup of chocolate chips for drizzling in a small microwave-safe bowl (about 1 minute on high power, stirring in 10-second increments until smooth).

Using a spoon, evenly drizzle the melted chocolate in vertical lines over the pie.

Allow the pie to cool on a wire rack for at least 4 hours (or overnight) before slicing and serving. This allows the chocolate drizzle to set and the interior of the pie to firm up.