How to make
Heat the oven to 360°F (180 °C). Sift the flour, baking powder and cocoa. To them add the yoghurt, egg and the butter, beaten with the sugar.
Add in the grated chocolate. Stir until you get a nice smooth mixture. Scoop from it and put a little at the bottom of each cupcake holder in an aluminum cupcake tray.
Put some blueberries in each one as well. Cover them with more of the mixture, the goal being to fill 2/3 of each little cupcake nest. Put the cupcake tray in the preheated oven.
After about 15-20 min. they should be ready. Take it out and cover with an oven dish for about 20 min., then serve.