Preheat oven (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer). Cream 250 g butter, sugar, vanilla sugar, 1 pinch of salt and saffron. Stir in eggs one at a time. Mix 250 g flour and baking powder and stir in portions alternately with apple juice.
Pour the dough into a greased and flour-dusted ring cake tin (approx. 2 l capacity). Bake in the hot 'oven for about 40 minutes. Let cool on a cake rack for about 10 minutes. Then turn out of the mould and let it cool down. Serve dusted with icing sugar. Red fruit jelly tastes good with it.