Blend the biscuits in a blender into fine crumbs.
In a bowl, stir the rest of the ingredients and add the biscuits. Beat with a mixer or hand blender briefly until you get a homogeneous mixture.
Pour the mixture into an oiled and sprinkled with cocoa form. I used a form 8 3/4″ (22 cm) in diameter with removable walls.
Bake the cake in a preheated 356°F (180 °C) oven for 15 min. or to a dry toothpick. Melt the chocolate in the milk in a water bath. Wait for it to cool a bit and pour it over the cake.