Melt butter and chocolate over low heat or in a water bath.
Beat the eggs with sugar until it is completely dissolved.
Pour the chocolate-butter mixture into the egg, without stopping beating with a mixer.
Add the sifted flour with cocoa powder and baking powder. Mix well and get a dough of this consistency.
I take paper forms, put them in silicone, fill them with 2/3 of the dough and send them to the steamer. From this amount, I get 8 cakes.
Turn on the steamer for 30 minutes.