Position oven rack to center of oven and preheat to 350°F/177°C. Line the bottom of 2, 8 inch (20 cm) round cake tins with parchment paper and grease the sides.

To a mixing bowl, sift together the flour, baking soda, baking powder, salt and cocoa, set aside.

To a large bowl beat the butter and sugar until light and fluffy, about 4 to 5 minutes. Add the eggs to the butter and sugar one-at-a-time while beating then add the milk. If the mix looks curdled, you haven't ruined it. It just means the butter and sugar were not creamed enough. It will smooth out when you fold in the flour.

Add the chocolate to a microwave-safe bowl. Microwave on high in 30 second increments, stirring in between until melted. Set aside to cool for a minute or so, don't add hot chocolate to the butter.

Fold in the melted chocolate to the butter, then fold in the flour mix and fold until well mixed and you don't see anymore white flour.

Divide the batter evenly between the 2 cake pans and bake for 25-30 minutes (depending how your oven is calibrated) until a toothpick comes out clean when inserted in the center.

Remove the cakes from the oven and allow to cool in the pan for 10 minutes.

Turn the cakes onto a wire cooling rack and remove the parchment paper. Allow to cool completely.

Add the butter and sugar to a large bowl and beat until light and fluffy. Stir in the Bailey's until well mixed.

Using a spatula, spread half of the frosting onto the top of one of the cakes. Place the other layer on top and spread the top and sides with the remaining frosting.

Take a large piece of parchment paper and spread a thin, even layer of melted chocolate. Roll the paper tightly and refrigerate for 1 hour. Unroll the paper and the chocolate will break into bark pieces. Place in a bowl and refrigerate until ready to decorate the cake.