Warm milk, 1 tablespoon of sugar, and yeast are added to a small bowl. Allow to stand 510 minutes until frothy. This informs you that your yeast is living and it is willing to party.
Add flour, remaining sugar and salt and mix in a large bowl (or stand mixer). Include the yeast mixture, yogurt, vanilla and butter. Knead the dough 8-10 minutes until the dough becomes smooth and elastic. Should it be claggy, then sprinkle a little more flour.
Pour the dough into a greased bowl, cover it with a clean towel and allow it to rise in a warm area/place for 1-1.5 hours or till it doubles in volume.
Punch out the dough, roll it to a thickness of approximately 1/2 inch and roll it with your cookie cutter into circles. Put them in a tray covered with parchment, loosely covered, and leave to ferment further 3040 minutes.
Heat oil in a deep pan to 350°F (175°C). Bake the pieces of dough in batches of 2-3 minutes each side, till golden brown. Drain on a wire rack or paper towels.
Roll the donuts in granulated sugar, but when still warm. After being slightly cool, use the piping bag and make a hole, and fill it with any of your preferred cream, Nutella, or jam.