Preheat your oven to 350 F/180 C.
Spray an 8 inch round loose bottom/springform cake pan with non-stick spray. Alternatively, grease with butter. Line the bottom of the pan with parchment paper.
Mix together the flour, baking powder and 1 cup granulated sugar.
In a separate bowl, whisk together the eggs, sour cream, mandarin zest, mandarin juice and oil.
Pour the wet ingredients into the flour mix and mix well until everything is evenly combined.
Pour the batter into the prepared pan and bake for 45 - 60 minutes. Keep an eye on the cake. It is ready once it has risen and is golden brown.
While the cake is baking, get on with making the mandarin syrup. Heat the mandarin juice and 1 tablespoon of sugar over low heat in a small pot. Continue to stir until the syrup has just begun to bubble. It will have thickened and appear syrupy.
Once it has baked, remove the cake from the oven and immediately prick it all over with a toothpick. Brush the mandarin syrup over the top.
Leave the cake in the pan to cool completely before serving.