Put wheat flour, salt and vanilla sugar in a bowl.
Add plant milk and sugar to a sauce pan and heat the two ingredients briefly on the stove to 37° Celsius. This is the perfect temperature for the yeast.
Add yeast to the plant milk-sugar mixture and dissolve in it.
Add the yeast-milk-sugar mixture to the flour and knead the whole thing into a smooth dough using a food processor. To do this, let the food processor knead the dough for about 5-8 minutes on medium speed. The dough is ready when it is elastic and can be easily removed without sticking from the dough hook.
Put the yeast dough into a bowl greased with oil. Brush the surface of the dough with a little oil to prevent it from drying out. This is really important because otherwise you won't be able to form nice doughnuts when the surface gets dry.
Cover the bowl with a lid and put the dough in the refrigerator overnight.
The next day, take the dough out of the fridge and let it get used to room temperature for a few minutes.
Now divide the dough into eight equal pieces (about 80-100g)*. Shape the individual pieces of dough into nice round and smooth balls using the rounding method*. Place the balls on a baking tray covered with baking paper and let them rise for another 30 minutes at room temperature.
In the meantime, pour the peanut oil into the sauce pan, attach a thermometer and heat the oil over medium heat to 170° Celsius. If it ever gets too hot, take the pan back off the heat, let the oil cool a bit, and put the pan back on the stove. Keep the temperature constant at 170° Celsius to a maximum of 175° Celsius.
Now place the first doughnut in the hot oil with the top side facing down. Put the lid on the pan and fry the doughnut in the oil for 2 to 3 minutes maximum. Monitor the temperature. Then remove the pan lid, turn the doughnut and fry on the other side for another 2-3 minutes until golden brown.
Lift the doughnut out of the oil and let cool on a kitchen towel or similar.
Repeat the last two steps until all doughnuts are deep fried. Allow all doughnuts to cool thoroughly.
Pour cherry jam into a piping bag fitted with a long round nozzle. Carefully prick the doughnut with the nozzle. Also carefully fill the jam into the doughnut.
Once all the doughnuts are filled with jam, place sugar in a bowl. Dip the top of the doughnuts in the sugar and enjoy immediately.