Pre-heat your oven to 160C Fan/180C/350F/Gas Mark 4, and line a cupcake tin with cupcake cases
To make the sponge, mix together the butter and sugar, ideally using an electric mixer, until smooth and fluffy
Add the eggs and vanilla extract and whisk well
Then gently whisk in the self raising flour
Divide the mixture between the 12 cupcake cases
Bake them for 20-25 minutes or until a thin skewer inserted in the centre of the cupcakes comes out clean. Put them on a rack to cool completely
Use a cupcake corer or a knife to make a hole in the middle of each cupcake
Fill the holes with the raspberry jam. You can do this using a spoon or put the jam into a small piping bag, snip the end off and pipe it in
Make the buttercream by mixing together the butter and icing sugar, then add the vanilla extract and milk, and mix until smooth. You can do this by hand, but an electric whisk or stand mixer with paddle attachment will provide the best results. If the buttercream is too stiff, you can add a little more milk
Pipe the buttercream onto each cupcake using a piping bag fitted with a nozzle. Or spread on with a spoon. Then add a Jammie Dodger biscuit on top - it will go soft from contact with the buttercream so add as close to serving as possible
Store in an airtight container in a cool place, eat leftovers within 3 days