Preheat the oven to 180 C / Gas 4. Place cupcake cases into a tin.
In a bowl, cream together the butter and caster sugar. Once mixed together, gradually add the beaten eggs. Now add the self-raising flour and stir well. Once the flour is combined and there are no lumps, divide the mixture equally between the cupcake cases.
Bake in the oven for 15 to 18 minutes or until golden brown and bouncy to the touch.
Whilst the cakes are cooling, start making the icing. In a bowl, soften the butter with an electric hand whisk. Then gradually add the icing sugar until it is all combined all it forms a light, creamy icing mixture. Add the raspberry jam and stir gently with a spoon so that it is just marbled into the icing. Fill a piping bag with the icing and ice the cupcakes when they have cooled. Sprinkle with the sprinkles if you are using them. Enjoy!