Melt margarine in a 13 X 9 pan in a 350 degree oven. Empty Jiffy muffin mix into a bowl and stir until all the lumps are gone. Stir in sugar. Add beaten eggs and mix well with a spoon. Mix in cream corn, salt, vanilla, and sour cream. Pour over melted margarine and bake at 350 degrees for 45-50 minutes or until lightly browned. This cornbread also freezes very well.