1. Add the butter and sugar to a large bowl and mix on high until light and fluffy. Add the egg and mix until well combined. Next, mix flour, baking powder, cocoa, and salt and add to the bowl – mix/knead until you get a nice smooth dough. Shape it into a ball, flatten it and wrap in plastic wrap. Place in the fridge for about 30 minutes.

2. Preheat the oven to 180°C (350°F). Line two baking sheets with baking parchment and set aside. Roll out the dough on a floured surface and cut out 40 rounds – each about 6cm in diameter. Place them on the baking sheets and bake one baking sheet after another for about 8-10 minutes. Take out of the oven and let cool down on the baking sheet for a moment, then transfer to a cooling rack and let cool down completely. Repeat with the second baking sheet – do not turn off the oven.

3. Half the marshmallows. Turn half of the cookies (20) upside down and place them on a baking sheet. Place a marshmallow piece on each of those cookies. Brush some marmalade on the backside of the other cookies and set them aside. Place the ones with the marshmallows in the oven and bake them for about 2-3 minutes. Take them out and immediately place the cookies with the marmalade on top of the cookies with the marshmallows and press them together. Let cool down on a wire rack.

4. Chop the chocolate coating and melt it in the microwave or over a small pot with simmering water. Coat the cookies with the chocolate and let them cool down completely on a wire rack.