Sift the flour into a large bowl and make a well in the middle. Crumble the yeast a little and pour it into the well.
Heat the soymilk in a saucepan lukewarm, but not hot. Melt the margarine in it and dissolve a teaspoon of sugar. Pour about a quarter of the warmed milk into the well, mix with the yeast and cover with a little flour. Cover and let rise in a warm place - approx. 33 ° C - for about 11 minutes.
Then add all the other dough ingredients and knead together with the rest of the milk mixture using the dough hook of the mixer in about 5 minutes to form a smooth, easy-to-knead dough until it loosens from the bowl. Then work with your hands into an evenly smooth dough that does not stick to your fingers.
Cover the bowl with the dough and let it rise in a warm place until the dough has doubled in volume. This takes about 50 minutes.
In the meantime, pour the jam into a piping bag with the longest and thinnest nozzle.
After the walking time, knead the dough vigorously again and then roll it out on a floured work surface 2 cm high and cut out circles with a 7 cm diameter glass.
Place the cakes on a baking sheet lined with baking paper and cover with a cloth. Let rise again for about 25 minutes.
Heat the oil in a tall saucepan. It should be filled to a maximum of 2/3 with oil. To check whether the oil is hot enough, simply dip the end of a wooden spoon into it: as soon as bubbles appear on the wood, the fat is hot enough. Make sure that the fat is not too hot, otherwise the donuts will quickly darken on the outside but not yet fully baked on the inside. So only deep-fry at low to medium heat.
Place the dough pieces one by one in the hot fat with the underside up. Be very careful with them. Put the lid on the pot.
When the undersides are baked golden brown, carefully turn the donuts with a wooden spoon and deep fry on the other side until golden brown, this time without a lid. Each side takes about 1.5 - 2 minutes.
Lift the baked donuts out of the oil with a ladle and place them on a plate lined with kitchen paper and allow to drain well. Immediately sprinkle the top with powdered sugar. It is important that the donuts are still warm or have been taken fresh from the fat, otherwise the icing sugar will not stick to them. Then let it cool down a bit.
Now the Berliners can be filled with jam. To do this, insert the top of the piping bag sideways into the still lukewarm donuts and pierce through to the middle, if necessary, prick with a kebab skewer. Carefully circle so that there is some space for the jam in Berlin. Be careful that the puncture site does not become too large! Then pour the jam into the donuts as you feel and tilt them slightly to cool so that the jam does not run out while it is cooling.