Spread oil on the cavities of a silicone mini-ball cake mould (6 cavities of approx. 6.5 cm Ø; each with a capacity of approx. 80 ml) and place on the oven rack. Or grease a muffin tin (for 12 pieces). Finely chop the nuts. Mix with 40 g brown sugar and cinnamon. Cream butter, white sugar, vanillin sugar and salt. Stir in the eggs one by one. Mix flour and baking powder, alternating with crème fraîche and stir in briefly
Quarter the dough. Chill 2 quarters. Put 1 quarter into the ring cake tin. Sprinkle half of the nut mixture on top. Spread the next quarter on top
Slide the oven rack into the preheated oven (electric cooker: 175 °C/circulating air: 150 °C/gas: level 2) and bake for approx. 25 minutes. Cool in the mould for approx. 15 minutes. Turn out and let cool down. Bake 6 more wreaths in the same way using the rest of the dough and nut mixture. Sprinkle the wreaths with icing sugar and 1 tbsp. brown sugar