Melt chocolate and spread into egg molds. Freeze 15min. Cream together corn syrup, margarine and vanilla, then sugar. Place half the mixture into a separate container with lid, mix in yellow food coloring and place covered in freezer 5min. Remove from freezer and shape into small balls (one per whole egg), then return to freezer. Remove molded chocolate from freezer. Unmold half of them. Working quickly, add white cream to every chocolate half (molded and unmolded). Remove yellow balls from freezer and add one ball to each egg half still in the molds. You may return everything to freezer for a few minutes here while you prepare the melted chocolate to seal one half with ball and one half without - to form the eggs. Return to freezer for 15min before unmolding.