Preheat oven to 180 degrees C.
Sieve flour, baking powder, baking soda. Sieve two three times to incorporate air.
In another bowl mix condensed milk, orange juice, oil, sugar, vanilla essence and lemon juice.
Gradually add the flour mix to the wet ingredients making it into a smooth batter.
Add orange zest and mix well.
Pour into a greased and dusted tin and bake for about 30 minutes or till a skewer comes out clean.
Cool the cake for 10 minutes, invert it on a wire rack.
Trim the edges of the cake.
Prick the cake at regular intervals with a tooth pick.