Mix flour, 100 g sugar and salt in a large mixing bowl. Add eggs and butter in flakes. Warm the milk lukewarm (must not be too warm), crumble yeast into it and dissolve it while stirring. Pour onto the flour mixture and knead into a smooth dough with the dough hooks of the hand mixer. Cover and leave to rise in a warm place for about 50 minutes.
Then knead again well with floured hands. Roll out on a floured work surface to a thickness of approx. 2 cm. Cut out a circle (7 cm Ø). Place on 2 baking trays sprinkled with flour and leave to rise for another 30 minutes. Heat the oil in a wide saucepan. Bake yeast particles in it in 5 portions light brown on each side. Lift them out and let them drip off a little on a grid. Stir icing sugar and 2-3 tablespoons of water until smooth. Stir jam until smooth. Pour into a piping bag with a long, very thin spout and squirt into the doughnuts.
Bake yeast particles in it in 5 portions light brown on each side. Lift them out and let them drip off a little on a grid. Stir icing sugar and 2-3 tablespoons of water until smooth. Stir jam until smooth. Pour into a piping bag with a long, very thin spout and squirt into the doughnuts. Roll 10 doughnuts in 100 g sugar. Spread 10 doughnuts with icing and let them dry
waiting time approx. 1 1/2 hours