Line a baking tray with baking parchment or grease with butter.
To make the shortcrust pastry, mix the butter, sugar, vanilla extract and eggs with a hand or stand mixer until creamy. Add the flour and baking powder and knead to a smooth dough.
The dough should be quite soft now. Add it in little portions to our baking tray and then even out by pressing with your fingers until you achieve an even base. Alternatively, you could also use a rolling pin to even out the creases. Prick the base a few times with a fork, this will allow the steam to escape and the base to bake evenly.
Spread the apricot jam evenly on top using the back of a spoon or spatula.
In a saucepan, melt the butter and sugar. Add in the nuts while stirring continually. You should get a thick nutty mass.
Pour the mass over the apricot jam layer. Try to even out the surface by using a knife or spatula. This will ensure that bars bake evenly.
Bake the bars in the oven for about 27-30 minutes. Then leave to cool briefly.
It is important to cut the Nussecken while warm as after they could down they might break. First cut them into squares or rectangles and then slice them diagonally.
Leave to cool completely. Do not discard the baking parchment as you might need it for later.
Once the nussecken cooled down, you can melt the chocolate in a water bath or the microwave. Pour into a high container and dunk the corners into the chocolate. Place on the baking tray to cool down completely.
Notes
I would recommend checking out the step by step images in the main post.