Sieve flour and baking powder and mix well. Add melted butter and combine.
Divide the batter in two. In the second bowl, add cocoa powder and combine. Wrap the bowls and refrigerate for at least 3 hours (at best 1 night).
Transfer natural batter in a piping bag. Put 1 tsp cocoa batter in each greased mold.
Cover with natural batter. Make swirls with the wooden sticks to marble the batters.
Bake 3 min at 450°F (230°C) on natural convection. Turn off oven and continue to bake the madeleines for 5 minutes, oven closed. Remove from oven after these 5 minutes and leave to cool down.
There you are : your marble madeleines are ready !
