Preheat your oven to 350°F (175°C). In a large mixing bowl, whisk together the all-purpose flour, unsweetened cocoa powder, baking soda, and salt. In another bowl, beat the softened butter and granulated sugar until light and fluffy.

Add the egg and vanilla extract to the butter-sugar mixture, mixing until well incorporated. Gradually add the dry ingredients, alternating with the buttermilk and evaporated milk, stirring until just combined. Use a cookie scoop to drop heaping tablespoons onto a baking sheet. Bake for 10-12 minutes or until cakes spring back when pressed.

While the cakes cool, prepare the coconut-pecan filling by combining granulated sugar, egg yolks, and softened butter in a saucepan over medium heat. Whisk for about 5-7 minutes until thick and bubbling.

Remove from heat and stir in sweetened shredded coconut, chopped pecans, and vanilla extract. Allow the filling to cool slightly.

Once cakes have cooled, scoop the filling onto the flat side of one cake and top with another, pressing gently. Enjoy or store in an airtight container.