Preheat oven to 350 degrees.
Combine sugar and the egg in a mixing bowl and beat this until smooth and fluffy, using a whisk or a mixer.
Then add flour, baking powder and baking soda.
In a separate bowl, combine the wet ingredients -- milk, melted butter, apricot jam and the vinegar. Mix well.
Combine the wet and dry ingredients and mix well.
Pour into an oven-proof dish (about an 8x8 ) and bake for 45 to 50 minutes.
In a pot, melt together the ingredients for the sauce. When the cake is halfway baked, take it out of oven. Make holes in the cake and pour the sauce over the pudding. Return the pudding to the oven to finish cooking.
Serve warm with whipping cream.