• Preheat oven to 180°C/ 350°F and line 2x 20cm springforms or cake tins with baking parchment.
• Microwave the chocolate for 20 seconds or until fully melted, then set aside to cool.
• In a mixing bowl, mix butter and sugar until fluffy. Mix in eggs, orange extract, chocolate milk and buttermilk.
• Add flour, baking powder and cocoa powder, mix until well combined and then stir in the melted chocolate.
• Divide the cake mixture between the two cake tins.
• Bake for 30-35 minutes, then remove them from the oven and let them cool.

Make The Buttercream

• Microwave the chocolate for 20 seconds until melt and set it aside to cool completely.
• Whisk together the butter, icing sugar and cocoa powder.
• Whisk in orange extract and melted chocolate, then whisk until combined.

  Tip: The buttercream should have a spreadable consistency.

Build the cake

• Place the first layer of the cake onto a serving plate and spread about ⅓ of the buttercream evenly on top of the cake.
• Add the second layer of the cake and spread ⅓ of the chocolate orange buttercream on top.
• Place the remaining buttercream into a piping bag with a star tip and pipe swirls around the edge of the cake.
• Finally, place a slice of chocolate orange on top of each swirl.