Wash the orange hot, rub dry and finely grate the peel. Halve the orange and squeeze the juice. Stir fat, sugar, salt and orange peel for about 10 minutes until creamy. Stir in the eggs one by one.
Add crème fraîche and 4 tablespoons of orange juice and mix. Mix flour and baking powder and stir in briefly. Grease a ring cake tin (2 litres capacity) and dust with breadcrumbs.
Pour in half of the dough. Mix the remaining dough with poppy seed baking. Spread the poppy seed dough on the light-coloured dough and marble with a fork. Bake the cake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for about 1 hour.
Take out, let it cool for 5 minutes and turn it over onto a kitchen grid. Let it cool down and dust with icing sugar. Decorate the cake with candied orange slices or fresh orange wedges.