1. Preheat your oven to 180°C/Gas Mark 4 and grease and line 2 x 20cm loose bottom sandwich tins with parchment paper.
2. Crack the eggs into a large mixing bowl, add the oil, caster sugar and yoghurt. Whisk together until combined.
3. Sieve the flour, baking powder and ground ginger over the egg mixture. Using a spatula, gently fold in the flour until you have a smooth cake mixture.
4. Divide the mixture between the prepared tins. Bake for 20 minutes until the cake is risen and springs back when lightly pressed.
5. Cool in the tins for 5 minutes then transfer to a wire rack to cool completely.
6. To assemble, place one sponge on a serving plate and spread the yoghurt over the surface, top with the jam and swirl it into the yoghurt, sandwich together with the other sponge. Dust the top with icing sugar.