Beat the butter, sugar, salt, vanilla sugar and the egg together until frothy. Mix the flour, baking powder, cocoa, cinnamon and orange zest, add the orange juice to the egg-sugar mixture and use the hand mixer on a low speed to form a dough in five minutes.
Pour the dough into four greased molds (e.g. muffin tins or soufflé tins). Sink a piece of chocolate into each portion of the dough.
Bake in a preheated oven at 175 ° C for 10 - 12 minutes.
Enjoy while still warm, e.g., with ice cream or fruit as a dessert.