Coconut lovers, this Coconut Custard Tart with Chocolate Ganache is the tart for you. If the thought of covering up the coconut with chocolate ganache makes you sweat, then let me assure you, you can leave it out and be perfectly happy. But if you're like me and have chocoholic tendencies, you won't be able to resist.
Gently roll out the pie dough to 1/4 inch thickness and press into a tart pan, making sure that it is evenly pressed into the pan and up the sides. Trim the excess that is hanging over the edges. Place a sheet of aluminum foil on top of the dough and fill with ceramic pie weights or beans. Let it rest in the refrigerator for about 15 minutes.
Place the tart pan in the center of a baking sheet and bake for about 8-10 minutes, then remove the foil and pie weights. Take the egg white from one of the separated eggs and whisk. Lightly brush the egg white onto the par baked tart shell. Return the shell to the oven and continue to bake for another 10 minutes more, or until it is a light golden color. Remove from the oven and let it cool. Keep the the tart shell on the baking sheet.
As the shell cools, make the filling. In a medium bowl, whisk together the coconut milk, condensed milk, egg and remaining egg yolk. Carefully pour into the tart shell, sprinkle with coconut and return to oven. Bake for about 30 minutes, or until a knife inserted 1 inch from the edge of the pan emerges clean. Carefully remove from oven and let it cool completely on the counter. At this point, the tart can be kept in the refrigerator if you wish to cover with ganache at another time, or if you wish to enjoy the tart without the chocolate at all.
Toast the large coconut flakes by spreading them on a parchment covered baking sheet and placing in the oven. Bake for 5 minutes, tossing periodically. Remove to cool. To create white chocolate curls, microwave a block of white chocolate in 15 second increments until it is slightly malleable. Use a vegetable peeler to create curls and let it cool completely on waxed paper.
To make the chocolate ganache, place the chocolate chips in a small bowl. Heat the heavy cream in a small sauce pan, bringing it to a gentle simmer of medium heat. Pour the heavy cream over the chocolate chips and let it sit for about 5 minutes. Whisk the chocolate and cream together until fully blended, then stir in the butter until glossy. Let it cool slightly, but keep in mind that ganache will spread more easily when warm.
Starting from the center, spoon the chocolate ganache over the tart, carefully guiding the chocolate to the edges of the tart using the back of the spoon in a circular motion. Garnish with the toasted coconut and white chocolate curls.
Keep in the refrigerator until the ganache has completely cooled, or until you are ready to serve.
To Make Ahead: The tart can be made 1 to 2 days in advance and stored in the refrigerator.