Calf's Liver Berlin Style
Preheat the oven to 120°C (approximately 250°F). Rinse the liver, pat dry and remove any skin and veins. Rinse the apples, peel if desired, core and cut apples into 8 mm (approximately 1/4-inch) thick slices and sprinkle with lemon juice. Peel, halve and cut the onions into thin strips. Dredge the liver in flour, shaking off excess. Heat 2 tablespoons of butter in a skillet and saute the liver until golden brown on each side, about 2 minutes and remove. Season with salt and pepper and place on the middle rack of the oven until pink, about 10 minutes (or cook more or less, depending on the desired degree of doneness.) Add the remaining butter to the pan and saute the apple slices until golden brown on both sides and place on the liver. Saute the onion strips in the remaining butter until golden brown and spoon half over the apples. Continue cooking the remaining onions until dark brown, deglaze with the cognac and broth and boil down until syrupy. Transfer to a blender and puree along with the cream. Season with salt and pepper.
Place the liver with onions and apples on plates, drizzle with the sauce and serve garnished with marjoram.