Preheat your oven to 350°F (175°C). Lightly grease and flour two 9-inch round baking pans, or line them with parchment rounds.
In a large mixing bowl, blend together the cake mix, buttermilk, melted butter, eggs, and vanilla extract. Using an electric mixer, beat the mixture on medium speed for about 2 minutes until the batter becomes smooth and cohesive.
Gently incorporate the toasted pecans and coconut flakes into the batter using a spatula or spoon until evenly distributed.
Evenly divide the prepared batter between the two cake pans. Smooth the tops and bake in the preheated oven for 25 to 30 minutes, or until a toothpick inserted in the center of each cake comes out clean.
Allow the cakes to rest in the pans for 10 minutes before carefully removing them and placing on wire racks to cool fully.
To make the frosting, use a clean mixing bowl to beat the softened cream cheese and butter together until smooth and creamy in texture.
Gradually add the powdered sugar to the mixture, starting on low speed and increasing as it incorporates. Pour in the vanilla extract and enough heavy cream to reach a spreadable, fluffy consistency.
Once the cakes have cooled, set one layer on a cake stand or serving platter. Spread an even layer of frosting over the top.
Gently place the second layer over the first and frost the top and sides of the entire cake using an offset spatula.
Sprinkle the remaining coconut flakes and chopped pecans evenly across the top of the frosted cake for decoration.
Refrigerate the assembled cake for a minimum of 30 minutes prior to slicing to ensure cleaner cuts and a firmer set.