Preheat the oven to 180C/350F and line a 12 hole cupcake tray with liners.
Place the butter and sugar into a large bowl, or the bowl of your stand mixer and beat on medium speed until the mixture comes together - it won't fully cream together due to the butter/sugar ratio, but it first of all goes crumbly, then comes together slightly. At this stage add in the eggs and vanilla extract and mix on medium speed until smooth and well combined. This is when the mixture comes together.
Add in the vegetable oil and mix on medium speed until well combined and smooth, about 1 minute.
Add in the cocoa powder, flour, baking powder and salt and mix on low until the mixture starts to come together, then add in the milk and continue to mix on medium speed until everything is smooth and well combined. The mixture should be airy and it won't be super thick.
Place a Kraft/Werther's caramel into the bottom of each cupcake liner and then cover with 2tbsp of cupcake batter.
Place into the oven for 18-22 minutes (mine took 18 mins) until risen and an inserted skewer into the centre comes out clean - because of the caramel, don't insert the skewer all the way to the bottom.
Transfer to a wire rack as soon as possible to cool completely.
Make the frosting: break the chocolate into a heat proof bowl and add in the butter. Microwave in 20 second increments, stirring between each one, until everything is melted together and it's thickened slightly.
Spoon a little of the chocolate mixture into the centre of your cupcakes and then swirl with the back of a small spoon. Pop 2 or 3 Golden Eggs into the centre of each cupcake and leave to set.
Galaxy Golden Egg Cupcakes will keep in an airtight container, at room temperature, for 3 days.