For marinated beets coated with poppy seeds on horseradish sauce, first boil the beets the night before in salted water for about 50 minutes until soft. Peel the softly cooked beets and cut them in half, be sure to use disposable gloves, because the beets stain strongly! Dissolve brown sugar in warm water and mix with lemon juice, red wine vinegar, salt and pepper to make a marinade. Toss in the halved beets and marinate overnight.
For the batter, the next day separate the eggs and beat the egg whites until stiff. Mix flour, wine, soda water and yolks and add ground poppy seeds and salt. Finally fold in the beaten egg whites.
For the horseradish sauce, melt the butter, stir in the flour with a whisk and sweat briefly. Pour in apple juice and vegetable soup and let everything boil down well. Peel the apple, tear or grate with a horseradish grater (or grating iron) and stir into the sauce with the grated horseradish. Season with sugar, lemon juice and wine vinegar. Pour in the cream and season with salt. Bring to the boil again very briefly and keep warm.
Heat oil in a deep pan. Remove the beets from the marinade, dab them with kitchen roll, put them on a wooden skewer and dip them one by one into the batter. Fry in hot oil until golden brown. Then lift out, drain and cut in half. Spread horseradish sauce on plates, place beets on top and serve marinated beets coated with poppy seeds on horseradish sauce as desired.