Step 1: Preheat your oven to 350°F (175°C). Grease and flour two 9-inch round cake pans.
Step 2: In a large mixing bowl, whisk together the flour, sugar, cocoa powder, baking powder, baking soda, and salt until well combined.
Step 3: In a separate bowl, beat the eggs, then add the milk, vegetable oil, and vanilla extract. Mix until well combined.
Step 4: Gradually add the wet ingredients to the dry ingredients, mixing until just combined. Carefully stir in the boiling water until the batter is smooth (the batter will be thin).
Step 5: Divide the batter evenly between the prepared cake pans. Bake in the preheated oven for 30-35 minutes, or until a toothpick inserted into the center comes out clean.
Step 6: Remove the cakes from the oven and allow them to cool in the pans for 10 minutes. Then, turn them out onto wire racks to cool completely.
Step 7: In a medium saucepan, combine the sugar, evaporated milk, butter, and beaten egg yolks. Cook over medium heat, stirring constantly until the mixture thickens and begins to bubble (about 10 minutes).
Step 8: Remove from heat and stir in the vanilla extract, shredded coconut, and chopped pecans. Let the frosting cool to room temperature.
Step 9: Once the cakes are completely cooled, place one layer on a serving plate. Spread a generous amount of coconut-pecan frosting on top. Place the second layer on top and spread frosting over the top and sides of the cake.
Step 10: Slice the cake and serve. Enjoy the delicious layers of chocolate and coconut-pecan goodness!