• 225g unsalted butter, chopped
• 2 cups caster sugar
• ⅓ cup cocoa powder
• 1 tsp bicarb soda
• 4 eggs, lightly beaten
• 2⅔ cups self-raising flour
• ½ cup pure cream
• 200g block dark chocolate, finely chopped
• 100g unsalted butter, finely chopped, at room temperature
• 175g unsalted butter, chopped, at room temperature
• 1½ cups icing sugar mixture
• ½ cup chocolate-hazelnut spread
Grease two 20cm round cake pans. Line bases and sides with baking paper, extending paper 2cm above pan edges.
Combine butter, sugar, 2 cups water and combined sifted cocoa and soda in a large saucepan. Stir over a medium heat until sugar is dissolved and butter is melted. Bring to boil. Transfer to a large bowl. Cool, whisking occasionally.
Whisk in eggs and flour until smooth. Divide evenly between prepared pans.
Cook in moderately slow oven (160°C) for about 50 minutes, or until cooked when tested. Remove. Stand in pans for 20 minutes. Turn out onto wire racks to cool.
To make icing, stir cream and chocolate in a medium, heatproof bowl sitting over a saucepan of simmering water, until smooth. Remove bowl from heat. Gradually whisk in butter until combined. Refrigerate for 25 to 30 minutes, stirring every 10 minutes, until slightly thickened, a spreadable consistency and still glossy.
Meanwhile, to make the buttercream, beat butter in a small bowl of an electric mixer until pale and creamy. Gradually beat in ½ cup sugar at a time until combined. Stir in the spread.
Trim tops of cakes to sit flat. Cut each in half horizontally. Place one layer on a serving plate. Spread with ⅔ cup buttercream. Repeat layering cakes, spreading ⅔ cup buttercream between each layer.
Spread icing over top and side of cake. Decorate with Easter eggs and dust with cocoa if desired.