Start spooning the batter into your cupcake cases. Then add a triangle or two of Toblerone.
Continue to add more cake batter until the triangles are mostly submerged:
Don't worry if your Toberlone is a little exposed still like mine was. The cakes rose once baked so the chocolate didn't burn!
This experiment one weekend turned out to be one of the best ideas I'd had in a long time.
But then again, cake is always a good idea.