In a bowl add all-purpose flour, baking powder, baking soda, salt & mix well. Set aside.
In a jug add milk, lemon juice, orange juice & mix well. Sour milk is ready. Set aside.
In a bowl add eggs, vegetable oil, castor sugar & beat until well combined.
Add sour milk, lemon zest, orange zest & beat until well combined.
Add dry ingredients & mix well.
Grease 8 inch round baking pan & sprinkle flour on it.
Add cake batter in the pan and bake in preheated oven at 175 C for 30-35 minutes or until toothpick inserted in the center of the cake comes out clean.
Remove the cake from the oven & let it completely cool.
Run a knife around the edges to loosen them from the sides of the pan.
Transfer the cake to the wire rack.