Preheat oven (electric cooker: 180 °C/circulating air: 160 °C/gas: see manufacturer). Oil the twelve troughs of a muffin tray, dust with flour. For the dough, mix 100 ml oil, eggs, sugar, 100 g sour cream and half orange juice. Mix 120 g flour, orange peel, nuts and baking soda. Stir briefly with the egg and oil mixture until all ingredients are evenly mixed. Spread the dough into the bowls. Bake in a hot oven for about 15 minutes.
For the filling heat jelly in a pot. Mix in frozen berries. Remove muffins from the oven, let them cool down briefly and lift them out of their trays. Let them cool down.
Cut out 1 ball from each muffin and sprinkle with the rest of the juice. Whip the cream until stiff. Cream 200 g sour cream and 80 g icing sugar. Fold in the cream. Swirl berry jelly into the sour cream. Put some cream on each muffin. Place soaked balls on top. Dust with 2 tbsp. icing sugar.
With a ball cutter you can easily cut out small cake balls from the muffin.