Pre-heat the oven to 160C Fan/350F/Gas Mark 4 and grease and line a 2lb loaf tin
Mix together the butter and caster sugar using an electric mixer or a spoon until light and fluffy
Add the Nutella, eggs and milk and whisk in until smooth
Whisk in the flour and cocoa powder until fully combined, then stir in the hazelnuts
Pour the mixture into the loaf tin and bake for an hour and 5 minutes, or until a skewer inserted in the centre comes out clean. Leave to cool fully
To make the buttercream, use an electric mixer or a spoon to mix together the butter and icing sugar until they start to combine, then add the Nutella and milk and mix until smooth
Put it into a piping bag and pipe it onto the loaf cake, or spread on with a spoon or spatula
Decorate with the Kinder Bueno bars and some sprinkles too if you like!
Store in an airtight container in a cool place and eat within 3 days
Video
Notes
Make sure all your ingredients (particularly the butter/baking spread and eggs) are at room temperature before you start baking.
You can use any cocoa powder for the cake, of course the better quality it is, the better flavour it will have. Do make sure you are using cocoa powder and not a hot chocolate powder.
I used a baking spread for the cake and unsalted butter for the buttercream.
You will need a 2lb loaf tin for this recipe (you can test the size of your loaf tin by seeing how much water the tin can hold, 2lb will hold about 2 pints/1100ml of water). If you have a 1lb loaf tin, simply halve the ingredient amounts.
Although I provide cup measurements, I highly recommend weighing your ingredients out using digital kitchen scales*. It is the most accurate way to measure ingredients and will ensure the best results. Digital scales are very low cost and can be purchased for around £12 ($16.50) .
For teaspoon (tsp) and tablespoon (tbsp) measurements, please use measuring spoons* and not the type of spoons you eat with. Again this will ensure accuracy and provide the best results.
I've reduced the buttercream amount after feedback it was too much (what can I say... I love buttercream!). The previous quantities were 150g Butter, 300g Icing sugar and 200g Nutella.