For the dough, melt both types of chocolate in a saucepan in a water bath over low heat and allow to cool. Mix the margarine or butter with a mixer until smooth. Gradually add sugar and vanilla sugar while stirring, until a bond is formed.
Stir in each egg for about 30 seconds at the highest level. Mix the flour with the baking powder and stir in 2 portions alternately with the milk on a medium setting. Halve the dough and stir in the melted chocolate and cocoa powder under one half of the dough.
For each waffle, add about 1 tablespoon of each half of the batter to the waffle iron alternately (depends on the size of the waffle iron) and bake the waffles until the batter is used up. Let the baked waffles cool and dust with powdered sugar. Makes about 8 round heart wafers.