Melt the chocolate and set aside.
Add a cooking pot with water to boil and add butter, and sugar. Melt everything and stir well.
In a separate large saucepan, bring milk to a boil in then pour in the melted sugar and mix then and add the crushed tea biscuits, ground hazelnut, ground almond, and butter and mix well.
Add the rum to the dough and mix and take it of the heat.
Divide the dough into two parts and pour the chocolate into one of the parts and mix well.
Put the chocolate part in a greased baking dish with 7 x 7, then put the other half without chocolate on top and press it in order to get nice layers and remove any air bubbles.
Heat the milk, butter and sugar together in another smaller pan over low heat to prepare the frosting. Add chocolate and mix until the mixtures become homogeneous.
Pour it over the dough and spread evenly.
Let the cake cool in the refrigerator for 6 to 8 hours.
Before serving use a sharp knife to cut pieces with 1 x 3 inch size.