Line 12 cupcake tins with paper liners or grease them with nonstick baking spray.
In a large mixing bowl, combine the flour, cocoa powder, baking powder, and sugar. Whisk to combine.
In a medium mixing bowl, whisk together the eggs, vegetable oil, buttermilk, and vanilla extract.
Add the wet ingredients to the dry ingredients and fold them together gently, making sure not to overmix. Keep folding just until no large lumps of flour remain.
Fill each cupcake tin ¾ of the way full and bake the cupcakes for 12 to 15 minutes, or until a toothpick inserted into the center comes out clean.
Allow the cupcakes to cool completely on a wire rack before icing them.
To make frosting:
Heat the heavy cream in a small saucepan, just until it starts to steam and bubble around the edges.
Add the chopped chocolate, butter and vanilla to a large bowl. Pour the cream over the chocolate and allow it to sit for one minute.
Then, whisk the mixture together until smooth. Transfer the icing to the fridge and allow it to chill until fully set (about 4 hours). (NOTE: I would start making the filling while the mixture is chilling so that everything is ready to assemble once the frosting is ready.)
Once the icing has hardened, transfer it to the bowl of a stand mixer fitted with the whisk attachment and beat on medium-high speed until it is light and fluffy - about 2 minutes,
Transfer the icing to a piping bag fitted with your choice of tip and set aside until ready to use.
To make the filling:
In a small saucepan over medium heat, combine the cream, egg yolks, and brown sugar.
Heat until the mixture is bubbling and the sugar has dissolved-- about 4 minutes. Make sure to stir often.
Add the butter, coconut and pecans and stir to combine.
Allow the mixture to cool to room temperature before adding to the cupcakes.
Pipe a small ring of chocolate icing around the edge of each cupcake, making sure it is large enough to hold the filling in the center.
Then, fill each ring of icing with coconut pecan filling.
Enjoy immediately or store in an airtight container in the fridge for up to three days .
Storing: Once cooled and frosted, enjoy immediately or store in an airtight container in the fridge for up to three daysFreezing: To freeze frosted cupcakes, frost completely cooled cupcakes and place them on a sheet pan. Cover with plastic wrap and freeze for a few hours making sure the frosting freezes completely. When frozen solid, transfer them to an airtight container and freezer for up to 3 months. Thaw in the fridge overnight before serving.