Melt the margarine and mix in the Xylitol.
Beat the eggs and add to the above mixture and beat with a mixer.
Gradually add the flour and baking powder, vanilla and lemon juice and vinegar and salt and mix well for 2 minutes with a blender until a thick batter.
Pour into a round cake tin greased and bake 190 degrees for 30 minutes or until done.
Once done cool and cut in middle and sandwich together with Dalfour sugar free jam.