Preheat the oven to 350°F (175°C). Grease a 9x13-inch baking pan with 2 tablespoons vegetable shortening and set aside.
Spread the chopped pecans and sweetened coconut flakes in an even layer across the bottom of the prepared pan.
Prepare the chocolate cake mix according to the package instructions in a large bowl, then stir in the 8 ounces melted chocolate until combined.
Pour the cake batter evenly over the coconut and pecans in the pan.
In a medium bowl, beat the softened cream cheese with a hand mixer until smooth. Add the 1/2 cup melted butter and beat until combined.
Gradually add the 2 1/2 cups powdered sugar to the cream cheese mixture and beat on low until smooth and lump-free.
Use an ice cream scoop or spoon to drop dollops of the cream cheese mixture evenly over the cake batter.
Sprinkle the semisweet and white chocolate chips evenly over the top of the cake.
Bake at 350°F for about 40 minutes, or until the cake has set and the edges are firm.
Allow the cake to cool completely in the pan before adding the ganache.
To make the ganache, place 8 ounces chopped chocolate in a bowl. Heat the 1/2 cup heavy cream until just hot, pour over the chopped chocolate, let stand 1 minute, then stir until smooth.
Pour or spread the ganache over the cooled cake. If desired, garnish with extra chocolate chips or sprinkles. Let the ganache set before cutting into squares to serve.