Mix sour cream with soda. Add melted butter to sour cream, mix until smooth.
Gradually start adding the flour in small portions. After pouring 1.5 cups, check: if the dough sticks to your hands, pour the rest of the glass. Otherwise, not necessarily.
Knead the dough and divide it into 2 equal parts. Cut the oranges / lemons into small slices (with a crust) and beat in a blender. Mix ground lemon with 1 cup sugar.
Heat the oven to 180 degrees. Put half the dough as a base. Spread the dough over the entire surface of the mold, making small sides.
Lay out the filling and spread it evenly over the entire base. Mash the second part of the dough with your hands and close the filling with it.
For a golden crust, grease the cake with whipped yolk. Pry the cake with a fork. Bake for about 30 minutes. Then cool and put the cake out of the mold and sprinkle with powdered sugar.