Preheat your oven to 180c/160c fan and get your cupcake cases ready.
Beat together your butter and sugar until light and fluffy, and then add in the flour, cocoa powder and eggs.
Beat again until smooth - split between the 12 cases evenly.
Bake the cupcakes in the oven for 18-22 minutes, and then leave to cool fully.
For the Decoration
Carefully core out the middle of the cupcakes, and add a heaped tablespoon of Lindt spread for each cupcake. Push the bit of cupcake back in, or eat it!
Melt your Lindt chocolate carefully until smooth and leave to cool.
Beat your room temperature unsalted butter on it's own for a couple of minutes to loosen and get paler in colour.
Add the icing sugar in a little at a time until fully incorporated, and then add in the melted and slightly cooled chocolate and beat again.
Once made, pipe your buttercream onto your cupcakes, and add a Lindt Lindor truffle to the top of each cupcake!
Sprinkle with sprinkles if you fancy, and drizzle with an extra bit of chocolate if you fancy, and enjoy!
Notes
I used the Lindt chocolate spread in these, but you can easily use Nutella or the Gü spread instead - or leave it out completely.
If you want to use Lindt chocolate in the cake mixture instead of the cocoa powder, up the flour to 175g, and add in 150g of melted Lindt chocolate.