Whisk eggs and sugar.

Heat the water. While it boils, step it aside and place a bowl on it to melt the butter and chocolate.

Add milk to the chocolate and butter and continue mixing.

To finish your moist mixture, add the chocolate, butter and milk mixture to the mixture with eggs and sugar. Then, keep mixing but slow.

To prepare the dry mixture, put flour, cocoa, baking powder and salt in a bowl and mix it all well.

Then, combine the moist and dry mixture. It is important not to add the whole dry mixture to the moist one immediately. Add it gradually.

Then start filling the muffin tins with that mixture you made earlier.
Don’t add a lot of mixture at the beginning because you have to reckon you will still need to add the stuffing and the rest of the mixture to the mold after the stuffing. (This is optional, but I put nutella, you can also put jam or whatever you want).

Bake them in a preheated oven for about twenty minutes at 170°.