Peel and grate the carrots. Finely chop the nuts. Mix the flour, baking soda, cinnamon, sultanas and sugar.
Preheat the oven to 180 degrees (without preheating: convection 160 degrees). Spread butter on a deep baking sheet.
Beat the eggs until frothy, then gradually stir in the oil. Mix the custard with the carrot mixture. Spread this smooth on the baking sheet and then bake for 40 - 50 minutes.
Let cool on the baking sheet.
Beat all the ingredients for the cream in a bowl until frothy and spread on the cake. Form wavy lines with a tablespoon.