In a blender, add in oreo, milk and baking powder. Blend until smooth.
Transfer into a 6-inch round cake pan that has been greased and lined with parchement paper.
Steam in a pre-heated steamer for about 45 minutes to an hour until toothpick inserted in the center comes out clean. Make sure that either the lid is covered with cloth or the pan is covered with a cling film to make sure that no water droplets stain the cake.
To make the fudge, melt chocolate and milk in a double boiler or microwave oven and stir to combine. Serve warm.