In a large bowl stir together sugar,flour,cocoa,baking powder, baking soda and salt.
Add the eggs, milk, oil and vanilla and start beating with a hand mixer on medium speed for one minute or until everything is fully combined.
Stir in boiling water - the batter will be thin but don't worry as this is right. It makes the cupcakes very airy.
Fill the cupcake cases ⅔ with batter so that it gives enough space to grow.
Bake them for 18-22 minutes.
Cool them completely before frosting them.
Preparing the frosting:
Cream the butter until fluffy. Add 1 cup of powdered sugar and keep beating for another 2 minutes. Add the sour cream and the rest of the sugar and continue to beat for 2 minutes. In case your frosting is too thick, add some milk, if it is too liquid, add some sugar.Mix in the purple colouring.
Place some of the frosting on the cupcakes and decorate with coloured sugar if you wish or any other decoration you might have.
Recipe by Romanian Mum Blog at https://romanianmum.com/2015/06/glorious-chocolate-cupcakes.html