1 orange, finely grated zest only
2 tbsp orange marmalade
100g/3Β½oz dark brown sugar
1Β½ tsp ground ginger
175g/6oz self-raising flour
4 bulbs stem ginger, chopped, plus 2 tbsp ginger syrup from the jar
125g/4Β½oz unsalted butter, at room temperature, plus extra for greasing
2 free-range eggs
4 tbsp milk