Heat oven to 170 C. Line 12 regular-size muffin cups with paper liners.
Beat eggs and sugar in a bowl together for a few minutes. In a separate bowl melt butter and chocolate together, over hot water or simply use the microwave. Let it cool down slightly before adding to the mixture. Sift flour, cacao powder, baking powder and soda. Add milk, sour cream, salt and vanilla and mix together until everything is incorporated.
Pour the batter into each muffin cup, make sure not to overfill because they will grow too big in the oven! The secret to a perfect muffin is to pour the batter only by *half*!!
Bake for about 18-20 minutes or until a wooden pick inserted in centre of cupcake comes out clean. Cool in pan before removing from the pan to cooling rack.
While muffins are cooling down make your ganache!
Gently heat double cream over medium heat, move off the heat and add finely chopped dark chocolate. Stir until melted and smooth. Evenly spoon ganache on top of muffins, use a spoon or simply dip them in the ganache. Let it set for 30 minutes. To speed up the process transfer to the fridge for 10-20min.
For the lettering: Microwave 40g white and a tbsp of cream, mix with a spoon until melted and smooth. Transfer to a piping bag, cut a tiny hole with scissors and then get creative!