Melt the butter with the couverture in a bain marie and stir until the mixture is homogenized.
Remove from heat and add the milk and the sugar. Whisk constantly, add the eggs one by one.
Then add the vanilla extract, the baking powder, the salt, the cocoa powder and the flour and mix until smooth.
Add the chocolate chips, mix gently and refrigerate for half an hour until the mixture congeals.
Make small balls of the mixture and place them on a baking pan lined with parchment paper, leaving a gap between them. Bake in preheated oven at 180*C (350* F) for 10′-12’ minutes.
Let them cool and serve.