Mix all ingredients in a heat-proof mixing bowl (I use the bowl from my stand mixer) and set it over the pot of water.
Heat for 5-7 minutes until the mixture is warm and the egg whites have thickened - stir while heating to prevent burning.
Remove from heat and let the mixture sit for 30 minutes so that the coconut can absorb more of the moisture.
Preheat oven to 350 F.
Grease a 9 inch pie pan with non-stick cooking spray (I would not recommend a deep dish pan for this recipe).
Press coconut mixture into the pie pan, evenly distributing it and being sure to push it all the way up the sides of the pan.
Bake for 5-7 minutes until the edges of the crust just start to get golden.
Reduce heat to 325 F and bake for another 10-15 minutes until the edge of the crust is all a nice golden brown.
Chocolate Mousse Instructions
Melt chocolate in a double boiler or in the microwave.
Cool until it's warm to the touch, but not burning hot.
Bring the heavy whipping cream to a boil (you can do this on the stove or in the microwave).
Pour the heavy whipping cream over the melted chocolate and mix thoroughly. If the heavy whipping cream is not hot, it will cause the chocolate to harden and get chunky - not what you want for your mousse.
Mix in the egg yolk.
Whip the egg whites in a separate bowl until you get soft peaks - they will have the texture of shaving cream.
Mix the sugar into the egg whites a little bit at a time.
Fold the egg whites into the chocolate in very small spoonfuls. Be extremely gentle. You don't want to smash the fluffiness out of the egg whites.
Pour the mousse into the cooked pie crust.
Chill for at least two hours prior to serving.
Notes
This chocolate mousse recipe calls for heavy whipping cream. If you are bringing this pie to a seder, you should replace the heavy whipping cream with water since you can't have dairy at a meat-based seder meal. For other meals during Passover, check with your host to see if the meal will be dairy or not before deciding whether to use heavy whipping cream or water. Likewise, replace the milk chocolate with a bittersweet chocolate for non-dairy meals.