Sift together the flour, cardamom, baking ammonia, and baking soda.
In another large mixing bowl, whisk together the eggs and sugar until pale. Add in the heavy cream and kefir/sour cream. Then slowly add in the dry ingredients and stir until smooth. Cover the bowl and chill in fridge for at least 1 hour.
Heat the lard or vegetable oil to 355°F (180°C) in a large pot.
Roll out the dough on a floured surface. You may need to add a generous amount on flour to the dough so it rolls without sticking. Add just enough so that you can roll it easily. Roll the dough out until it's about 1/2 inch (1 cm) thick and cut out doughnut shapes.
Fry the smultringer until they are golden on each side. You can also fry the doughnut holes! Cool on a wire rack covered in paper towels.