Beat the butter and sugar until fluffy and light. Add the zest and eggs one at a time, beating well after each addition.
Sift the flour and ginger. Fold into the creamy mix.
Spread batter in a greased and lined 21 cm spring form tin.
Bake at 150°C for 50-60 minutes (or until cooked when tested).
Syrup
While the cake is cooking: place the syrup ingredients in a saucepan. Dissolve the sugar over a low heat. Increase the heat to high and bring to a boil. Skim off any scum that arises. Reduce heat slightly and simmer for 5 minutes.
Once cake is cooked leave in springform pan, pierce the top of the cake all over with a skewer, carefully pour the hot syrup over the cake. Leave to cool completely.
Remove the cake from the pan and slice into wedges. Serve with cream or Creme Fraiche.