Pre-heat your oven to 160C Fan/180C/350F/Gas Mark 4, and grease and line three 8" cake tins that are at least 2" deep
Make the sponge by mixing the butter and light brown soft sugar together until fluffy, ideally using an electric mixer
Add the eggs and vanilla extract, and whisk until fully incorporated
Add the self raising flour and whisk in gently until you can't see any flour anymore
Divide the mixture between the tins, use scales for accuracy if you like
Bake them for 30-35 minutes or until a skewer inserted in the middle comes out clean. Leave them to fully cool either in the tins or on cooling racks
If the cakes have domed on top, level them off with a cake leveller
To make the buttercream, mix together the butter and icing sugar, for best results use an electric mixer
When it starts to come together add the salted caramel sauce and milk, and whisk until smooth. If it is too stiff, you can add more milk
Stack the sponges up on your plate or cake stand, piping or spreading buttercream between each layer and drizzling salted caramel sauce over the buttercream
When you get to the last layer, pipe large rosettes all around the edge
Drizzle over more salted carmel sauce, and add fudge sprinkles if using or any other sprinkles you like
Serve immediately, store leftovers in an airtight container in a cool place and eat within 3 days