Pre-heat oven on gas mark 4. Put paper cases into a 12-hole cake tin.
Add the butter and sugar to a mixing bowl and then mix until incorporated. Then add the eggs and mix in. Once the eggs are incorporated, add the flour and fold in until incorporated then add the milk. Mix until incorporated.
Using an ice cream scoop, scoop the mixture into the cases and bake in the oven for 20 minutes. Once the cakes are done, leave them to cool in the tin for a minute then transfer to a cooling rack until cooled completely.
Add the butter to a bowl and mix until fluffy and pale. Once the butter is done, add the icing sugar a bit at a time until fully added and incorporated.
Fill a piping bag that has a star nozzle on it and pipe on a swirl to the cooled cupcakes. Once buttercream is on the cupcakes, add the caramel popcorn and drizzle over some caramel sauce.