For the choux:

1. Preheat the oven to 425 degrees and line a baking sheet with a sheet of parchment paper. Fit a piping bag with a large round tip (I use Ateco 809) or snip the end off of a quart-sized freezer plastic bag.
2. In a medium saucepan over medium heat, combine the water, butter, sugar and salt until the butter has melted and the mixture is boiling. Remove the saucepan from the heat and add all of the flour, stirring vigorously to combine. After a few moments of stirring, the dough will form a moist ball that pulls away from the sides of the pan. Return the pan back to the heat to cook, paddling the dough with a wooden spoon or rubber spatula for 3 minutes. Dump the dough into a large bowl and add the eggs one at a time, stirring vigorously after each addition to combine.  The dough should be viscous enough to hold a soft peak when you pull the wooden spoon out of it. If it is too stiff, add a teaspoon or two of water. Scoop the mixture into the piping bag and squeeze out tablespoon-sized round balls (see photo) of dough, about 2 inches apart on the prepared pan. Barely moisten a fingertip to smooth out any peaks on the rounds so that they are rounded disks, similar to the shape of a baked macaron cookie. Bake in the preheated oven for 10 minutes, then decrease the oven temp to 350 and bake an additional 15-20 minutes, or until the puffs are golden brown. Allow to cool prior to using.

To prepare the filling:

1. In a medium saucepan, combine sugar, flour, and salt, whisking to combine. Slowly add the milk. Turn heat to medium temperature and whisk constantly until the mixture is bubbling and thickened. Continue to cook for an additional 2 minutes.
2. Slowly drizzle a small amount of the cooked mixture into the beaten egg yolks, whisking all the while. Once about a cup of the mixture is incorporated, pour the mixture back into the original saucepan and place back on the heat. Cook an additional 1-2 minutes while continuing to stir.
3. Add the butter and vanilla, stirring until incorporated. Stir in the coconut. Allow to cool to room temperature. You can do this in the fridge as well. When cool, stir and outfit a piping back with a large round tip. Fill the bag with the custard and insert the tip discreetly into the side of a crack in a puff. Fill with the custard slowly until full and then repeat with the remaining. Set aside while you melt the chocolate for the topping. 

For the topping:

1. Set up a double boiler over low heat and add the white chocolate to the bowl. Stirring regularly, gently melt the chocolate. Be sure to not let the chocolate get too hot or it will seize! Once my chocolate starts melting a good bit, I usually remove the pan and bowl from heat to stop the cooking and keep it going gently. Once melted, spoon pours of white chocolate on top of each pastry and sprinkle with toasted coconut. Enjoy once the topping has set!