Preparation: 

1. Heat milk and butter in a pot

2. Add flour in a bowl and mix with sugar, vanilla sugar and salt

3. Add yeast in crumbles and pour milk-butter mix over

4. Add yolk and knead all ingredients into an even dough for 5 minutes

5. Cover dough and let it rest for 30 Minutes 

6. Knead dough on a surface covered with flour. Then divide into 12 even pieces

7. Form into balls and place on a baking tray with enough space in between. Cover with kitchen cloth and let it rise for another 30 minutes

8. Heat oil in a pot. Carefully add balls into fat. Reduce heat and bake doughnut from both sides for around 3 minutes until gold-brown. Low heat is needed to allow the doughnut to bake inside. Remove from the fat using a dipper and let them cool out on a piece of kitchen paper.

9. Fill the cooled out doughnuts with Marmetube raspberry. Poke a small hole into the side of the ball, so the opening of the tube can fit inside.

10. Sprinkle powdered sugar over doughnuts before serving