Mix yeast and sugar together in a large bowl, preferably in a stand mixer.
Add the milk and then salt, eggs, butter, and cardamom.
Mix well before adding half of the flour.
Run it well in the machine, and then gradually add about 1 dl of flour until the dough comes away from the sides of the bowl as it is mixed.
Cover with a clean dish towel and let the dough rest for about 60 minutes.
Sprinkle flour on the table and use a rolling pin to roll out the dough into a large square, which you can divide into about 20 equal squares.
Place a spoonful of custard and a piece of light chocolate on top, fold each corner of the squares into the center to form a bun. Turn them over so the seam is down and press them slightly flat if needed.
Cover with a clean dish towel and let them rise for another 30 minutes.
Brush the buns with a beaten egg and bake them at 200 degrees Celsius (392 degrees Fahrenheit) convection for 18 minutes.
Combine sugar and eggs in a bowl. Whisk until it becomes foamy and light (like an eggnog).
Add the flour and whisk it in to avoid lumps.
Bring the milk to a boil in a saucepan with the vanilla pod. Stir continuously to prevent it from burning.
Pour the hot milk into the bowl with the egg mixture while whisking vigorously.
Then, return the mixture to the saucepan. Optionally, scrape the seeds from the vanilla pod, adding them to the cream. Discard the pod.
Heat the saucepan again and whisk until it boils while stirring.
Pour it into a new bowl and refrigerate until it sets.
Mix cocoa, powdered sugar, and half of the boiling water together in a bowl.
Stir well and gradually add 1 tbsp of water until you achieve the desired thickness.
Decorate your cooled Shrovetide buns with the glaze and finish with the gold dust/glitter.
Enjoy.