Pre-heat the oven to 180C/160C Fan/350F/Gas Mark 4, and grease and line a 8" cake tin (that is at least 2" deep)
Cream together the dark brown sugar and the butter
Whisk in the eggs, vanilla extract and yoghurt
Mix in the cinnamon, ground ginger, ground cardamom, plain flour and baking powder
Pour the batter into the cake tin, add blobs of the jam all over the top and use a knife to gently swirl the mixture around.
Bake for 35 minutes, or until a skewer inserted comes out clean and it is golden brown all over, remove from the tin and leave to cool on a cooling rack
When cool, dust all over with icing sugar, I recommend serving with double cream or custard!
Store leftovers in an airtight container in a cool place and eat within 3 days