For the cake
2 and 1/2 cups Gold Medal all-purpose flour
1 teaspoon baking soda
1/2 teaspoon salt
4 ounces Hershey’s semisweet chocolate finely chopped
1 cup Land O’ Lakes unsalted butter softened
2 cups granulated sugar
4 large eggs
1 teaspoon McCormick vanilla extract
2/3 cup Hershey’s unsweetened cocoa powder plus more for dusting the pan
1 and 1/2 cups canned coconut milk
For the filling
1 cup canned coconut milk
4 large egg yolks
1/3 cup granulated sugar
2 and 1/2 tablespoons Argo cornstarch
1 teaspoons coconut extract
2 tablespoons unsalted butter cut into pieces
1/2 cup shredded sweetened coconut
For the frosting
coconut buttercream frosting (or any frosting of your choice)
For the glaze
4 ounces semisweet chocolate coarsely chopped
4 tablespoons unsalted butter cut into pieces
2 tablespoons light corn syrup
1/2 to 1 cup shredded sweetened coconut
Heat the oven to 325°F. Spray 3 (8-inch) round pans with baking spray. Line the bottoms with parchment paper cut into a circle to fit the pan. Spray the parchment paper with nonstick spray and dust the pan lightly with cocoa powder. Tap out any excess and set aside.
Combine the flour, baking soda, and salt. Stir and set aside.
Melt the chocolate in the microwave in 10 second increments, stirring in between, until it’s fully melted. Alternatively you can add the chocolate to a small heatproof bowl and set it over a pot of barely simmering water. Keep stirring until melted and smooth. Remove from heat and set aside to cool.
Beat the butter and sugar together until light and fluffy. Beat in the eggs, one at a time, mixing well after each addition. Scrape down the sides of the bowl as needed. Beat in the vanilla. Add the cocoa powder and melted chocolate, mix until well combined. With the mixer set to low speed, gradually add half the flour mixture, followed by the coconut milk, and then the remaining flour mixture. Beat just until combined. The batter will be thick.
Divide the batter evenly between the 3 prepared pans. Spread the batter all the way to the edges of the pan and smooth out the surface. Bake for 28-30 minutes, or until a toothpick inserted into the center comes out with only a few dry crumbs. Cool the cake in the pans for 10 minutes, then invert the cakes onto a wire rack to cool completely.
Bring the coconut milk up to a simmer in a medium saucepan. In a separate bowl, whisk the egg yolks, sugar, cornstarch, and extract until blended and pale in color. Slowly pour in the hot milk while whisking continuously. Return the mixture back to the saucepan and whisk over medium-high heat until thickened, about 3 minutes. Pour the thickened pastry cream through a fine mesh sieve, then stir in the butter until fully melted. Place a piece of plastic wrap directly on top of the pastry cream, making sure it is touching the surface, and refrigerate until cooled completely. Stir in the shredded coconut.
Place one of the cake layers on a serving plate, bottom side up. Spread half the pastry cream over the top, leaving a 1/2-inch margin around the edge. Top with another cake layer. Repeat with remaining pastry cream and top with the third cake layer.
Spread the frosting over the top and sides of the cake. Using a large cake scraper, remove frosting from the sides of the cake until the cake layers begin to show through.
Make the glaze
Place the chocolate, butter, and corn syrup in a medium heatproof bowl set over a pot of barely simmering water. Stir until melted and smooth. Remove from heat and let cool for 5 minutes.
Spoon 1/4 cup of the chocolate glaze over the top of the cake. Drizzle the remaining glaze along the edge of the cake, allowing it to drip down the sides all around. Sprinkle shredded coconut over the top.