1 lemon, zest only
1 orange, zest only
75g/3oz marmalade
200g/7oz plain flour
2 tsp baking powder
125²µ/4½ caster sugar
50ml/2fl oz vegetable oil
3 free-range eggs
125²µ/4½oz full-fat Greek-style yoghurt
Greek-style yoghurt
1 tbsp orange juice