Preheat oven to 350°F (180°C).
Line 24 muffin tins with cupcake liners.
Combine flour, cocoa, sugar, baking powder, salt, and pudding mix in a large mixing bowl. Add in eggs and butter, beating until smooth.
Carefully add melted butter and vanilla to the mix, mixing on medium speed until smooth.
Add buttermilk to batter, mix until well incorporated and smooth.
Use food colouring to tint batter black.
Divide batter among prepared muffin pans. Bake until golden and knife inserted into center of batter comes out clean - about 20-22 mins .
Allow to cool to cool to room temperature, before decorating.
Prepare either Swiss meringue buttercream or American buttercream, following the applicable recipe and flavouring and colouring it as you like.
Frost your cupcake as desired, enjoy!