First step: Preheat the oven to 180C/350F/Gas mark 4. Grab a separate bowl and add the self-raising flour, unprocessed cocoa powder, baking powder and whisk until well combined. Set aside for later.
Second step: Whisk the unsalted butter and caster sugar in a bowl for 3-5 minutes or until it is nearly white in colour.
Third step: Crack the eggs open in a bowl and add 1 tsp of hazelnut. Add 1/4 of the eggs to the bowl and whisk well (until you can no longer see the eggs). Repeat this process for the rest of the eggs in the bowl.
Fourth step: Add half of the flour mixture to the butter mix and gradually add the milk. Use a large spoon or hand held whisk to mix all of the ingredients together. Repeat this step with the second half of the flour mixture until you get a silky consistency.
Fifth step: Grab some lightly greased 6″ non-stick cake tins and use a spoon to add equal amounts of the cake batter to each tin. Place the tins in the oven on the middle shelf and leave to bake for 25-30 minutes. Stick a skewer in each cake and if the skewer comes out clean then the cakes are ready.
Sixth step: Leave to cool on a rack for 2 hours or until cool before you start decorating.