Pre heat the oven to 180 deg fan assisted. Grease and line the base of 2 x 19cm/7.5” loose bottomed cake tin.
Beat together the butter and sugar until light and fluffy
Add the eggs one at a time, adding a little flour between each egg. This will help prevent curdling. Mix until well combined.
Add the vanilla extract, cocoa and remaining flour. Gently mix until well combined
Pour the cake batter evenly into the prepared cake tins. Bake for 20 - 25 mins. Or until baked. Testing the centre of the cakes with a skewer until it comes out clean.
Leave in the tins to cool a little before turning out onto a wire rack to cool completely.
Turning one of the cakes upside down while cooling, will help flatten the dome a little. Making it easier to sandwich the two layers together.
Adding the filling and topping.
Melt the chocolate and butter in a heat proof bowl over a pan of simmering water. Stir frequently until melted and smooth. Leave to one side to cool a little.
Sandwich the two cake layers together, keeping the flattened done one upside down, with the Hazelnut spread. Feel free to be generous with the filling and use the whole jar. Using a piping bag will make the job easier.
Pour the cooled chocolate mix over the top of the cake.
Before it sets completely, decorate with the mini eggs
Notes
Will keep for a couple of days in an air tight tin.